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rfc:rfc2911

Network Working Group T. Hastings, Editor Request for Comments: 2911 R. Herriot Obsoletes: 2566 Xerox Corporation Category: Standards Track R. deBry

                                             Utah Valley State College
                                                           S. Isaacson
                                                          Novell, Inc.
                                                             P. Powell
                                                   Astart Technologies
                                                        September 2000
        Internet Printing Protocol/1.1: Model and Semantics

Status of this Memo

 This document specifies an Internet standards track protocol for the
 Internet community, and requests discussion and suggestions for
 improvements.  Please refer to the current edition of the "Internet
 Official Protocol Standards" (STD 1) for the standardization state
 and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

 Copyright (C) The Internet Society (2000).  All Rights Reserved.

Abstract

 This document is one of a set of documents, which together describe
 all aspects of a new Internet Printing Protocol (IPP).  IPP is an
 application level protocol that can be used for distributed printing
 using Internet tools and technologies.  This document describes a
 simplified model consisting of abstract objects, their attributes,
 and their operations that is independent of encoding and transport.
 The model consists of a Printer and a Job object.  A Job optionally
 supports multiple documents.  IPP 1.1 semantics allow end-users and
 operators to query printer capabilities, submit print jobs, inquire
 about the status of print jobs and printers, cancel, hold, release,
 and restart print jobs.  IPP 1.1 semantics allow operators to pause,
 resume, and purge (jobs from) Printer objects.  This document also
 addresses security, internationalization, and directory issues.

Hastings, et al. Standards Track [Page 1] RFC 2911 IPP/1.1: Model and Semantics September 2000

 The full set of IPP documents includes:
   Design Goals for an Internet Printing Protocol [RFC2567]
   Rationale for the Structure and Model and Protocol for the Internet
   Printing Protocol [RFC2568]
   Internet Printing Protocol/1.1: Model and Semantics (this document)
   Internet Printing Protocol/1.1: Encoding and Transport [RFC2910]
   Internet Printing Protocol/1.1: Implementer's Guide [IPP-IIG]
   Mapping between LPD and IPP Protocols [RFC2569]
 The "Design Goals for an Internet Printing Protocol" document takes a
 broad look at distributed printing functionality, and it enumerates
 real-life scenarios that help to clarify the features that need to be
 included in a printing protocol for the Internet.  It identifies
 requirements for three types of users: end users, operators, and
 administrators.  It calls out a subset of end user requirements that
 are satisfied in IPP/1.0.  A few OPTIONAL operator operations have
 been added to IPP/1.1.
 The "Rationale for the Structure and Model and Protocol for the
 Internet Printing Protocol" document describes IPP from a high level
 view, defines a roadmap for the various documents that form the suite
 of IPP specification documents, and gives background and rationale
 for the IETF working group's major decisions.
 The "Internet Printing Protocol/1.1: Encoding and Transport" document
 is a formal mapping of the abstract operations and attributes defined
 in the model document onto HTTP/1.1 [RFC2616].  It defines the
 encoding rules for a new Internet MIME media type called
 "application/ipp".  This document also defines the rules for
 transporting over HTTP a message body whose Content-Type is
 "application/ipp".  This document defines a new scheme named 'ipp'
 for identifying IPP printers and jobs.
 The "Internet Printing Protocol/1.1: Implementer's Guide" document
 gives insight and advice to implementers of IPP clients and IPP
 objects.  It is intended to help them understand IPP/1.1 and some of
 the considerations that may assist them in the design of their client
 and/or IPP object implementations.  For example, a typical order of
 processing requests is given, including error checking.  Motivation
 for some of the specification decisions is also included.
 The "Mapping between LPD and IPP Protocols" document gives some
 advice to implementers of gateways between IPP and LPD (Line Printer
 Daemon) implementations.

Hastings, et al. Standards Track [Page 2] RFC 2911 IPP/1.1: Model and Semantics September 2000

Table of Contents

 1.   Introduction                                                 9
 1.1   Simplified Printing Model                                  10
 2.   IPP Objects                                                 12
 2.1   Printer Object                                             13
 2.2   Job Object                                                 15
 2.3   Object Relationships                                       16
 2.4   Object Identity                                            17
 3.   IPP Operations                                              20
 3.1   Common Semantics                                           21
 3.1.1  Required Parameters                                       21
 3.1.2  Operation IDs and Request IDs                             22
 3.1.3  Attributes                                                22
 3.1.4  Character Set and Natural Language Operation Attribute    24
 3.1.4.1   Request Operation Attributes                           25
 3.1.4.2   Response Operation Attributes                          29
 3.1.5  Operation Targets                                         30
 3.1.6  Operation Response Status Codes and Status Messages       32
 3.1.6.1   "status-code" (type2 enum)                             32
 3.1.6.2   "status-message" (text(255))                           33
 3.1.6.3   "detailed-status-message" (text(MAX))                  33
 3.1.6.4   "document-access-error" (text(MAX))                    34
 3.1.7  Unsupported Attributes                                    34
 3.1.8  Versions                                                  36
 3.1.9  Job Creation Operations                                   38
 3.2   Printer Operations                                         41
 3.2.1  Print-Job Operation                                       41
 3.2.1.1   Print-Job Request                                      41
 3.2.1.2   Print-Job Response                                     46
 3.2.2  Print-URI Operation                                       48
 3.2.3  Validate-Job Operation                                    49
 3.2.4  Create-Job Operation                                      49
 3.2.5  Get-Printer-Attributes Operation                          50
 3.2.5.1   Get-Printer-Attributes Request                         51
 3.2.5.2   Get-Printer-Attributes Response                        53
 3.2.6  Get-Jobs Operation                                        54
 3.2.6.1   Get-Jobs Request                                       54
 3.2.6.2   Get-Jobs Response                                      56
 3.2.7  Pause-Printer Operation                                   57
 3.2.7.1   Pause-Printer Request                                  59
 3.2.7.2   Pause-Printer Response                                 60
 3.2.8  Resume-Printer Operation                                  60
 3.2.9  Purge-Jobs Operation                                      61
 3.3   Job Operations                                             62
 3.3.1  Send-Document Operation                                   62
 3.3.1.1   Send-Document Request                                  64
 3.3.1.2   Send-Document Response                                 65

Hastings, et al. Standards Track [Page 3] RFC 2911 IPP/1.1: Model and Semantics September 2000

 3.3.2  Send-URI Operation                                        66
 3.3.3  Cancel-Job Operation                                      66
 3.3.3.1   Cancel-Job Request                                     67
 3.3.3.2   Cancel-Job Response                                    68
 3.3.4  Get-Job-Attributes Operation                              69
 3.3.4.1   Get-Job-Attributes Request                             69
 3.3.4.2   Get-Job-Attributes Response                            70
 3.3.5  Hold-Job Operation                                        71
 3.3.5.1   Hold-Job Request                                       72
 3.3.5.2   Hold-Job Response                                      73
 3.3.6  Release-Job Operation                                     74
 3.3.7  Restart-Job Operation                                     75
 3.3.7.1   Restart-Job Request                                    76
 3.3.7.2   Restart-Job Response                                   78
 4.   Object Attributes                                           78
 4.1   Attribute Syntaxes                                         78
 4.1.1  'text'                                                    79
 4.1.1.1   'textWithoutLanguage'                                  80
 4.1.1.2   'textWithLanguage'                                     80
 4.1.2  'name'                                                    81
 4.1.2.1   'nameWithoutLanguage'                                  82
 4.1.2.2   'nameWithLanguage'                                     82
 4.1.2.3   Matching 'name' attribute values                       83
 4.1.3  'keyword'                                                 84
 4.1.4  'enum'                                                    85
 4.1.5  'uri'                                                     85
 4.1.6  'uriScheme'                                               86
 4.1.7  'charset'                                                 86
 4.1.8  'naturalLanguage'                                         87
 4.1.9  'mimeMediaType'                                           87
 4.1.9.1 Application/octet-stream -- Auto-Sensing                 88
         the document format
 4.1.10 'octetString'                                             89
 4.1.11 'boolean'                                                 89
 4.1.12 'integer'                                                 89
 4.1.13 'rangeOfInteger'                                          90
 4.1.14 'dateTime'                                                90
 4.1.15 'resolution'                                              90
 4.1.16 '1setOf  X'                                               90
 4.2   Job Template Attributes                                    91
 4.2.1  job-priority (integer(1:100))                             94
 4.2.2  job-hold-until (type3 keyword | name (MAX))               95
 4.2.3  job-sheets (type3 keyword | name(MAX))                    96
 4.2.4  multiple-document-handling (type2 keyword)                96
 4.2.5  copies (integer(1:MAX))                                   98
 4.2.6  finishings (1setOf type2 enum)                            98
 4.2.7  page-ranges (1setOf rangeOfInteger (1:MAX))              101
 4.2.8  sides (type2 keyword)                                    102

Hastings, et al. Standards Track [Page 4] RFC 2911 IPP/1.1: Model and Semantics September 2000

 4.2.9  number-up (integer(1:MAX))                               102
 4.2.10 orientation-requested (type2 enum)                       103
 4.2.11 media (type3 keyword | name(MAX))                        104
 4.2.12 printer-resolution (resolution)                          105
 4.2.13 print-quality (type2 enum)                               105
 4.3   Job Description Attributes                                106
 4.3.1  job-uri (uri)                                            107
 4.3.2  job-id (integer(1:MAX))                                  108
 4.3.3  job-printer-uri (uri)                                    108
 4.3.4  job-more-info (uri)                                      108
 4.3.5  job-name (name(MAX))                                     108
 4.3.6  job-originating-user-name (name(MAX))                    109
 4.3.7  job-state (type1 enum)                                   109
 4.3.7.1   Forwarding Servers                                    112
 4.3.7.2   Partitioning of Job States                            112
 4.3.8  job-state-reasons (1setOf  type2 keyword)                113
 4.3.9  job-state-message (text(MAX))                            118
 4.3.10 job-detailed-status-messages (1setOf text(MAX))          118
 4.3.11 job-document-access-errors (1setOf text(MAX))            118
 4.3.12 number-of-documents (integer(0:MAX))                     119
 4.3.13 output-device-assigned (name(127))                       119
 4.3.14 Event Time Job Description Attributes                    119
 4.3.14.1  time-at-creation (integer(MIN:MAX))                   120
 4.3.14.2  time-at-processing (integer(MIN:MAX))                 120
 4.3.14.3  time-at-completed (integer(MIN:MAX))                  120
 4.3.14.4  job-printer-up-time (integer(1:MAX))                  120
 4.3.14.5  date-time-at-creation (dateTime)                      121
 4.3.14.6  date-time-at-processing (dateTime)                    121
 4.3.14.7  date-time-at-completed (dateTime)                     121
 4.3.15 number-of-intervening-jobs (integer(0:MAX))              121
 4.3.16 job-message-from-operator (text(127))                    121
 4.3.17 Job Size Attributes                                      121
 4.3.17.1  job-k-octets (integer(0:MAX))                         122
 4.3.17.2  job-impressions (integer(0:MAX))                      122
 4.3.17.3  job-media-sheets (integer(0:MAX))                     123
 4.3.18 Job Progress Attributes                                  123
 4.3.18.1  job-k-octets-processed (integer(0:MAX))               123
 4.3.18.2  job-impressions-completed (integer(0:MAX))            123
 4.3.18.3  job-media-sheets-completed (integer(0:MAX))           124
 4.3.19 attributes-charset (charset)                             124
 4.3.20 attributes-natural-language (naturalLanguage)            124
 4.4   Printer Description Attributes                            124
 4.4.1  printer-uri-supported (1setOf uri)                       126
 4.4.2  uri-authentication-supported (1setOf type2 keyword)      127
 4.4.3  uri-security-supported (1setOf type2 keyword)            128
 4.4.4  printer-name (name(127))                                 129
 4.4.5  printer-location (text(127))                             129
 4.4.6  printer-info (text(127))                                 130

Hastings, et al. Standards Track [Page 5] RFC 2911 IPP/1.1: Model and Semantics September 2000

 4.4.7  printer-more-info (uri)                                  130
 4.4.8  printer-driver-installer (uri)                           130
 4.4.9  printer-make-and-model (text(127))                       130
 4.4.10 printer-more-info-manufacturer (uri)                     130
 4.4.11 printer-state (type1 enum)                               131
 4.4.12 printer-state-reasons (1setOf type2 keyword)             131
 4.4.13 printer-state-message (text(MAX))                        134
 4.4.14 ipp-versions-supported (1setOf type2 keyword)            134
 4.4.15 operations-supported (1setOf type2 enum)                 135
 4.4.16 multiple-document-jobs-supported (boolean)               136
 4.4.17 charset-configured (charset)                             136
 4.4.18 charset-supported (1setOf charset)                       137
 4.4.19 natural-language-configured (naturalLanguage)            137
 4.4.20 generated-natural-language-supported
        (1setOf naturalLanguage)                                 137
 4.4.21 document-format-default (mimeMediaType)                  138
 4.4.22 document-format-supported (1setOf mimeMediaType)         138
 4.4.23 printer-is-accepting-jobs (boolean)                      138
 4.4.24 queued-job-count (integer(0:MAX))                        138
 4.4.25 printer-message-from-operator (text(127))                139
 4.4.26 color-supported (boolean)                                139
 4.4.27 reference-uri-schemes-supported (1setOf uriScheme)       139
 4.4.28 pdl-override-supported (type2 keyword)                   139
 4.4.29 printer-up-time (integer(1:MAX))                         140
 4.4.30 printer-current-time (dateTime)                          140
 4.4.31 multiple-operation-time-out (integer(1:MAX))             141
 4.4.32 compression-supported (1setOf type3 keyword)             141
 4.4.33 job-k-octets-supported (rangeOfInteger(0:MAX))           142
 4.4.34 job-impressions-supported (rangeOfInteger(0:MAX))        142
 4.4.35 job-media-sheets-supported (rangeOfInteger(0:MAX))       142
 4.4.36 pages-per-minute (integer(0:MAX))                        142
 4.4.37 pages-per-minute-color (integer(0:MAX))                  142
 5.   Conformance                                                143
 5.1   Client Conformance Requirements                           143
 5.2   IPP Object Conformance Requirements                       145
 5.2.1  Objects                                                  145
 5.2.2  Operations                                               145
 5.2.3  IPP Object Attributes                                    146
 5.2.4  Versions                                                 146
 5.2.5  Extensions                                               147
 5.2.6  Attribute Syntaxes                                       147
 5.2.7  Security                                                 148
 5.3   Charset and Natural Language Requirements                 148
 6.   IANA Considerations                                        148
 6.1   Typed 'keyword' and 'enum' Extensions                     149
 6.2   Attribute Extensibility                                   151
 6.3   Attribute Syntax Extensibility                            152
 6.4   Operation Extensibility                                   152

Hastings, et al. Standards Track [Page 6] RFC 2911 IPP/1.1: Model and Semantics September 2000

 6.5   Attribute Group Extensibility                             153
 6.6   Status Code Extensibility                                 153
 6.7   Out-of-band Attribute Value Extensibility                 154
 6.8   Registration of MIME types/sub-types for document-formats 154
 6.9   Registration of charsets for use in 'charset'
       attribute values                                          154
 7.   Internationalization Considerations                        154
 8.   Security Considerations                                    158
 8.1   Security Scenarios                                        159
 8.1.1  Client and Server in the Same Security Domain            159
 8.1.2  Client and Server in Different Security Domains          159
 8.1.3  Print by Reference                                       160
 8.2   URIs in Operation, Job, and Printer attributes            160
 8.3   URIs for each authentication mechanisms                   160
 8.4   Restricted Queries                                        161
 8.5   Operations performed by operators and system
       administrators                                            161
 8.6   Queries on jobs submitted using non-IPP protocols         162
 9.   References                                                 162
 10.  Authors' Addresses                                         166
 11.  Formats for IPP Registration Proposals                     168
 11.1  Type2 keyword attribute values registration               169
 11.2  Type3 keyword attribute values registration               169
 11.3  Type2 enum attribute values registration                  169
 11.4  Type3 enum attribute values registration                  170
 11.5  Attribute registration                                    170
 11.6  Attribute Syntax registration                             171
 11.7  Operation registration                                    171
 11.8  Attribute Group registration                              171
 11.9  Status code registration                                  172
 11.10 Out-of-band Attribute Value registration                  172
 12.  APPENDIX A: Terminology                                    173
 12.1  Conformance Terminology                                   173
 12.1.1 NEED NOT                                                 173
 12.2  Model Terminology                                         173
 12.2.1 Keyword                                                  173
 12.2.2 Attributes                                               173
 12.2.2.1  Attribute Name                                        173
 12.2.2.2  Attribute Group Name                                  174
 12.2.2.3  Attribute Value                                       174
 12.2.2.4  Attribute Syntax                                      174
 12.2.3 Supports                                                 174
 12.2.4 print-stream page                                        176
 12.2.5 impression                                               177
 13. APPENDIX B: Status Codes and Suggested Status Code Messages 177
 13.1  Status Codes                                              178
 13.1.1 Informational                                            178
 13.1.2 Successful Status Codes                                  178

Hastings, et al. Standards Track [Page 7] RFC 2911 IPP/1.1: Model and Semantics September 2000

 13.1.2.1  successful-ok (0x0000)                                178
 13.1.2.2  successful-ok-ignored-or-substituted-attributes
           (0x0001)                                              179
 13.1.2.3  successful-ok-conflicting-attributes (0x0002)         179
 13.1.3 Redirection Status Codes                                 179
 13.1.4 Client Error Status Codes                                179
 13.1.4.1  client-error-bad-request (0x0400)                     180
 13.1.4.2  client-error-forbidden (0x0401)                       180
 13.1.4.3  client-error-not-authenticated (0x0402)               180
 13.1.4.4  client-error-not-authorized (0x0403)                  180
 13.1.4.5  client-error-not-possible (0x0404)                    180
 13.1.4.6  client-error-timeout (0x0405)                         181
 13.1.4.7  client-error-not-found (0x0406)                       181
 13.1.4.8  client-error-gone (0x0407)                            181
 13.1.4.9  client-error-request-entity-too-large (0x0408)        182
 13.1.4.10 client-error-request-value-too-long (0x0409)          182
 13.1.4.11 client-error-document-format-not-supported (0x040A)   182
 13.1.4.12 client-error-attributes-or-values-not-supported
           (0x040B)                                              183
 13.1.4.13 client-error-uri-scheme-not-supported (0x040C)        183
 13.1.4.14 client-error-charset-not-supported (0x040D)           183
 13.1.4.15 client-error-conflicting-attributes (0x040E)          183
 13.1.4.16 client-error-compression-not-supported (0x040F)       184
 13.1.4.17 client-error-compression-error (0x0410)               184
 13.1.4.18 client-error-document-format-error (0x0411)           184
 13.1.4.19 client-error-document-access-error (0x0412)           184
 13.1.5    Server Error Status Codes                             185
 13.1.5.1  server-error-internal-error (0x0500)                  185
 13.1.5.2  server-error-operation-not-supported (0x0501)         185
 13.1.5.3  server-error-service-unavailable (0x0502)             185
 13.1.5.4  server-error-version-not-supported (0x0503)           185
 13.1.5.5  server-error-device-error (0x0504)                    186
 13.1.5.6  server-error-temporary-error (0x0505)                 186
 13.1.5.7  server-error-not-accepting-jobs (0x0506)              187
 13.1.5.8  server-error-busy (0x0507)                            187
 13.1.5.9  server-error-job-canceled (0x0508)                    187
 13.1.5.10 server-error-multiple-document-jobs-not-supported
           (0x0509)                                              187
 13.2  Status Codes for IPP Operations                           187
 14.  APPENDIX C:  "media" keyword values                        190
 15.  APPENDIX D: Processing IPP Attributes                      208
 15.1  Fidelity                                                  209
 15.2  Page Description Language (PDL) Override                  210
 15.3  Using Job Template Attributes During Document Processing  212
 16.  APPENDIX E: Generic Directory Schema                       214
 17.  APPENDIX F:  Differences between the IPP/1.0 and IPP/1.1
      "Model and Semantics" Documents                            215
 18.  Full Copyright Statement                                   224

Hastings, et al. Standards Track [Page 8] RFC 2911 IPP/1.1: Model and Semantics September 2000

1. Introduction

 The Internet Printing Protocol (IPP) is an application level protocol
 that can be used for distributed printing using Internet tools and
 technologies.  IPP version 1.1 (IPP/1.1) focuses primarily on end
 user functionality with a few administrative operations included.
 This document is just one of a suite of documents that fully define
 IPP.  The full set of IPP documents includes:
   Design Goals for an Internet Printing Protocol [RFC2567]
   Rationale for the Structure and Model and Protocol for the Internet
   Printing Protocol [RFC2568]
   Internet Printing Protocol/1.1: Model and Semantics (this document)
   Internet Printing Protocol/1.1: Encoding and Transport [RFC2910]
   Internet Printing Protocol/1.1: Implementer's Guide [IPP-IIG]
   Mapping between LPD and IPP Protocols [RFC2569]
 Anyone reading these documents for the first time is strongly
 encouraged to read the IPP documents in the above order.
 This document is laid out as follows:
  1. The rest of Section 1 is an introduction to the IPP simplified

model for distributed printing.

  1. Section 2 introduces the object types covered in the model with

their basic behaviors, attributes, and interactions.

  1. Section 3 defines the operations included in IPP/1.1. IPP

operations are synchronous, therefore, for each operation, there is

   a both request and a response.
 - Section 4 defines the attributes (and their syntaxes) that are used
   in the model.
 - Sections 5 - 6 summarizes the implementation conformance
   requirements for objects that support the protocol and IANA
   considerations, respectively.
 - Sections 7 - 11 cover the Internationalization and Security
   considerations as well as References, Author contact information,
   and Formats for Registration Proposals.
 - Sections 12 - 14 are appendices that cover Terminology, Status
   Codes and Messages, and "media" keyword values.
     Note: This document uses terms such as "attributes", "keywords",
     and "support".  These terms have special meaning and are defined
     in the model terminology section 12.2.  Capitalized terms, such
     as MUST, MUST NOT, REQUIRED, SHOULD, SHOULD NOT, MAY, NEED NOT,
     and OPTIONAL, have special meaning relating to conformance.
     These terms are defined in section 12.1 on conformance
     terminology, most of which is taken from RFC 2119 [RFC2119].

Hastings, et al. Standards Track [Page 9] RFC 2911 IPP/1.1: Model and Semantics September 2000

  1. Section 15 is an appendix that helps to clarify the effects of

interactions between related attributes and their values.

  1. Section 16 is an appendix that enumerates the subset of Printer

attributes that form a generic directory schema. These attributes

   are useful when registering a Printer so that a client can find the
   Printer not just by name, but by filtered searches as well.
 - Section 17 is an appendix summarizing the additions and changes
   from the IPP/1.0 "Model and Semantics" document [RFC2566] to make
   this IPP/1.1 document.
 - Section 18 is the full copyright notice.

1.1 Simplified Printing Model

 In order to achieve its goal of realizing a workable printing
 protocol for the Internet, the Internet Printing Protocol (IPP) is
 based on a simplified printing model that abstracts the many
 components of real world printing solutions.  The Internet is a
 distributed computing environment where requesters of print services
 (clients, applications, printer drivers, etc.) cooperate and interact
 with print service providers.  This model and semantics document
 describes a simple, abstract model for IPP even though the underlying
 configurations may be complex "n-tier" client/server systems.  An
 important simplifying step in the IPP model is to expose only the key
 objects and interfaces required for printing.  The model described in
 this model document does not include features, interfaces, and
 relationships that are beyond the scope of the first version of IPP
 (IPP/1.1).  IPP/1.1 incorporates many of the relevant ideas and
 lessons learned from other specification and development efforts
 [HTPP] [ISO10175] [LDPA] [P1387.4] [PSIS] [RFC1179] [SWP].  IPP is
 heavily influenced by the printing model introduced in the Document
 Printing Application (DPA) [ISO10175] standard.  Although DPA
 specifies both end user and administrative features, IPP version 1.1
 (IPP/1.1) focuses primarily on end user functionality with a few
 additional OPTIONAL operator operations.
 The IPP/1.1 model encapsulates the important components of
 distributed printing into two object types:
  1. Printer (Section 2.1)
  2. Job (Section 2.2)
 Each object type has an associated set of operations (see section 3)
 and attributes (see section 4).

Hastings, et al. Standards Track [Page 10] RFC 2911 IPP/1.1: Model and Semantics September 2000

 It is important, however, to understand that in real system
 implementations (which lie underneath the abstracted IPP/1.1 model),
 there are other components of a print service which are not
 explicitly defined in the IPP/1.1 model. The following figure
 illustrates where IPP/1.1 fits with respect to these other
 components.
                              +--------------+
                              |  Application |
                    o         +. . . . . . . |
                   \|/        |   Spooler    |
                   / \        +. . . . . . . |   +---------+
                 End-User     | Print Driver |---|  File   |
       +-----------+ +-----+  +------+-------+   +----+----+
       |  Browser  | | GUI |         |                |
       +-----+-----+ +--+--+         |                |
             |          |            |                |
             |      +---+------------+---+            |
 N   D   S   |      |      IPP Client    |------------+
 O   I   E   |      +---------+----------+
 T   R   C   |                |
 I   E   U   |
 F   C   R   -------------- Transport ------------------
 I   T   I
 C   O   T                    |         --+
 A   R   Y           +--------+--------+  |
 T   Y               |    IPP Server   |  |
 I                   +--------+--------+  |
 O                            |           |
 N                   +-----------------+  | IPP Printer
                     |  Print Service  |  |
                     +-----------------+  |
                              |         --+
                     +-----------------+
                     | Output Device(s)|
                     +-----------------+
 An IPP Printer object encapsulates the functions normally associated
 with physical output devices along with the spooling, scheduling and
 multiple device management functions often associated with a print
 server. Printer objects are optionally registered as entries in a
 directory where end users find and select them based on some sort of
 filtered and context based searching mechanism (see section 16).  The
 directory is used to store relatively static information about the
 Printer, allowing end users to search for and find Printers that
 match their search criteria, for example: name, context, printer
 capabilities, etc.  The more dynamic information, such as state,
 currently loaded and ready media, number of jobs at the Printer,

Hastings, et al. Standards Track [Page 11] RFC 2911 IPP/1.1: Model and Semantics September 2000

 errors, warnings, and so forth, is directly associated with the
 Printer object itself rather than with the entry in the directory
 which only represents the Printer object.
 IPP clients implement the IPP protocol on the client side and give
 end users (or programs running on behalf of end users) the ability to
 query Printer objects and submit and manage print jobs.  An IPP
 server is just that part of the Printer object that implements the
 server-side protocol.  The rest of the Printer object implements (or
 gateways into) the application semantics of the print service itself.
 The Printer objects may be embedded in an output device or may be
 implemented on a host on the network that communicates with an output
 device.
 When a job is submitted to the Printer object and the Printer object
 validates the attributes in the submission request, the Printer
 object creates a new Job object.  The end user then interacts with
 this new Job object to query its status and monitor the progress of
 the job.  An end user can also cancel their print jobs by using the
 Job object's Cancel-Job operation.  An end-user can also hold,
 release, and restart their print jobs using the Job object's OPTIONAL
 Hold-Job, Release-Job, and Restart-Job operations, if implemented.
 A privileged operator or administrator of a Printer object can
 cancel, hold, release, and restart any user's job using the REQUIRED
 Cancel-Job and the OPTIONAL Hold-Job, Release-Job, and Restart-Job
 operations.  In additional privileged operator or administrator of a
 Printer object can pause, resume, or purge (jobs from) a Printer
 object using the OPTIONAL Pause-Printer, Resume-Printer, and Purge-
 Jobs operations, if implemented.
 The notification service is out of scope for this IPP/1.1 document,
 but using such a notification service, the end user is able to
 register for and receive Printer specific and Job specific events.
 An end user can query the status of Printer objects and can follow
 the progress of Job objects by polling using the Get-Printer-
 Attributes, Get-Jobs, and Get-Job-Attributes operations.

2. IPP Objects

 The IPP/1.1 model introduces objects of type Printer and Job.  Each
 type of object models relevant aspects of a real-world entity such as
 a real printer or real print job.  Each object type is defined as a
 set of possible attributes that may be supported by instances of that
 object type.  For each object (instance), the actual set of supported
 attributes and values describe a specific implementation.  The
 object's attributes and values describe its state, capabilities,
 realizable features, job processing functions, and default behaviors

Hastings, et al. Standards Track [Page 12] RFC 2911 IPP/1.1: Model and Semantics September 2000

 and characteristics.  For example, the Printer object type is defined
 as a set of attributes that each Printer object potentially supports.
 In the same manner, the Job object type is defined as a set of
 attributes that are potentially supported by each Job object.
 Each attribute included in the set of attributes defining an object
 type is labeled as:
  1. "REQUIRED": each object MUST support the attribute.
  2. "RECOMMENDED": each object SHOULD support the attribute.
  3. "OPTIONAL": each object MAY support the attribute.
 Some definitions of attribute values indicate that an object MUST or
 SHOULD support the value; otherwise, support of the value is
 OPTIONAL.
 However, if an implementation supports an attribute, it MUST support
 at least one of the possible values for that attribute.

2.1 Printer Object

 The major component of the IPP/1.1 model is the Printer object.  A
 Printer object implements the server-side of the IPP/1.1 protocol.
 Using the protocol, end users may query the attributes of the Printer
 object and submit print jobs to the Printer object.  The actual
 implementation components behind the Printer abstraction may take on
 different forms and different configurations.  However, the model
 abstraction allows the details of the configuration of real
 components to remain opaque to the end user.  Section 3 describes
 each of the Printer operations in detail.
 The capabilities and state of a Printer object are described by its
 attributes.  Printer attributes are divided into two groups:
  1. "job-template" attributes: These attributes describe supported job

processing capabilities and defaults for the Printer object. (See

   section 4.2)
 - "printer-description" attributes: These attributes describe the
   Printer object's identification, state, location, references to
   other sources of information about the Printer object, etc. (see
   section 4.4)
 Since a Printer object is an abstraction of a generic document output
 device and print service provider, a Printer object could be used to
 represent any real or virtual device with semantics consistent with
 the Printer object, such as a fax device, an imager, or even a CD
 writer.

Hastings, et al. Standards Track [Page 13] RFC 2911 IPP/1.1: Model and Semantics September 2000

 Some examples of configurations supporting a Printer object include:
    1) An output device with no spooling capabilities
    2) An output device with a built-in spooler
    3) A print server supporting IPP with one or more associated
       output devices
       3a) The associated output devices may or may not be capable of
           spooling jobs
       3b) The associated output devices may or may not support IPP
 The following figures show some examples of how Printer objects can
 be realized on top of various distributed printing configurations.
 The embedded case below represents configurations 1 and 2. The hosted
 and fan-out figures below represent configurations 3a and 3b.
 In this document the term "client" refers to a software entity that
 sends IPP operation requests to an IPP Printer object and accepts IPP
 operation responses.  A client MAY be:
    1. contained within software controlled by an end user, e.g.
       activated by the "Print" menu item in an application or
    2. the print server component that sends IPP requests to either an
       output device or another "downstream" print server.
 The term "IPP Printer" is a network entity that accepts IPP operation
 requests and returns IPP operation responses.  As such, an IPP object
 MAY be:
    1. an (embedded) device component that accepts IPP requests and
       controls the device or
    2. a component of a print server that accepts IPP requests (where
       the print server controls one or more networked devices using
       IPP or other protocols).
 Legend:
 ##### indicates a Printer object which is
       either embedded in an output device or is
       hosted in a server.  The Printer object
       might or might not be capable of queuing/spooling.
 any   indicates any network protocol or direct
       connect, including IPP

Hastings, et al. Standards Track [Page 14] RFC 2911 IPP/1.1: Model and Semantics September 2000

 embedded printer:
                                           output device
                                         +---------------+
  O   +--------+                         |  ###########  |
 /|\  | client |------------IPP------------># Printer #  |
 / \  +--------+                         |  # Object  #  |
                                         |  ###########  |
                                         +---------------+
 hosted printer:
                                         +---------------+
  O   +--------+        ###########      |               |
 /|\  | client |--IPP--># Printer #-any->| output device |
 / \  +--------+        # Object  #      |               |
                        ###########      +---------------+
                                          +---------------+
 fan out:                                 |               |
                                      +-->| output device |
                                  any/    |               |
  O   +--------+      ###########   /     +---------------+
 /|\  | client |-IPP-># Printer #--*
 / \  +--------+      # Object  #   \     +---------------+
                      ########### any\    |               |
                                      +-->| output device |
                                          |               |
                                          +---------------+

2.2 Job Object

 A Job object is used to model a print job.  A Job object contains
 documents.  The information required to create a Job object is sent
 in a create request from the end user via an IPP Client to the
 Printer object.  The Printer object validates the create request, and
 if the Printer object accepts the request, the Printer object creates
 the new Job object.  Section 3 describes each of the Job operations
 in detail.
 The characteristics and state of a Job object are described by its
 attributes.  Job attributes are grouped into two groups as follows:
  1. "job-template" attributes: These attributes can be supplied by

the client or end user and include job processing instructions

      which are intended to override any Printer object defaults
      and/or instructions embedded within the document data. (See
      section 4.2)

Hastings, et al. Standards Track [Page 15] RFC 2911 IPP/1.1: Model and Semantics September 2000

  1. "job-description" attributes: These attributes describe the Job

object's identification, state, size, etc. The client supplies

      some of these attributes, and the Printer object generates
      others. (See section 4.3)
 An implementation MUST support at least one document per Job object.
 An implementation MAY support multiple documents per Job object.  A
 document is either:
  1. a stream of document data in a format supported by the Printer

object (typically a Page Description Language - PDL), or

  1. a reference to such a stream of document data
 In IPP/1.1, a document is not modeled as an IPP object, therefore it
 has no object identifier or associated attributes.  All job
 processing instructions are modeled as Job object attributes.  These
 attributes are called Job Template attributes and they apply equally
 to all documents within a Job object.

2.3 Object Relationships

 IPP objects have relationships that are maintained persistently along
 with the persistent storage of the object attributes.
 A Printer object can represent either one or more physical output
 devices or a logical device which "processes" jobs but never actually
 uses a physical output device to put marks on paper.  Examples of
 logical devices include a Web page publisher or a gateway into an
 online document archive or repository.  A Printer object contains
 zero or more Job objects.
 A Job object is contained by exactly one Printer object, however the
 identical document data associated with a Job object could be sent to
 either the same or a different Printer object.  In this case, a
 second Job object would be created which would be almost identical to
 the first Job object, however it would have new (different) Job
 object identifiers (see section 2.4).
 A Job object is either empty (before any documents have been added)
 or contains one or more documents.  If the contained document is a
 stream of document data, that stream can be contained in only one
 document.  However, there can be identical copies of the stream in
 other documents in the same or different Job objects.  If the
 contained document is just a reference to a stream of document data,
 other documents (in the same or different Job object(s)) may contain
 the same reference.

Hastings, et al. Standards Track [Page 16] RFC 2911 IPP/1.1: Model and Semantics September 2000

2.4 Object Identity

 All Printer and Job objects are identified by a Uniform Resource
 Identifier (URI) [RFC2396] so that they can be persistently and
 unambiguously referenced.  Since every URL is a specialized form of a
 URI, even though the more generic term URI is used throughout the
 rest of this document, its usage is intended to cover the more
 specific notion of URL as well.
 An administrator configures Printer objects to either support or not
 support authentication and/or message privacy using Transport Layer
 Security (TLS) [RFC2246] (the mechanism for security configuration is
 outside the scope of this IPP/1.1 document).  In some situations,
 both types of connections (both authenticated and unauthenticated)
 can be established using a single communication channel that has some
 sort of negotiation mechanism.  In other situations, multiple
 communication channels are used, one for each type of security
 configuration.  Section 8 provides a full description of all security
 considerations and configurations.
 If a Printer object supports more than one communication channel,
 some or all of those channels might support and/or require different
 security mechanisms.  In such cases, an administrator could expose
 the simultaneous support for these multiple communication channels as
 multiple URIs for a single Printer object where each URI represents
 one of the communication channels to the Printer object. To support
 this flexibility, the IPP Printer object type defines a multi-valued
 identification attribute called the "printer-uri-supported"
 attribute.  It MUST contain at least one URI.  It MAY contain more
 than one URI.  That is, every Printer object will have at least one
 URI that identifies at least one communication channel to the Printer
 object, but it may have more than one URI where each URI identifies a
 different communication channel to the Printer object.  The
 "printer-uri-supported" attribute has two companion attributes, the
 "uri-security-supported" attribute and the "uri-authentication-
 supported". Both have the same cardinality as "printer-uri-
 supported".  The purpose of the "uri-security-supported" attribute is
 to indicate the security mechanisms (if any) used for each URI listed
 in "printer-uri-supported". The purpose of the "uri-authentication-
 supported" attribute is to indicate the authentication mechanisms (if
 any) used for each URI listed in "printer-uri-supported".  These
 three attributes are fully described in sections 4.4.1, 4.4.2, and
 4.4.3.
 When a job is submitted to the Printer object via a create request,
 the client supplies only a single Printer object URI.  The client
 supplied Printer object URI MUST be one of the values in the
 "printer-uri-supported" Printer attribute.

Hastings, et al. Standards Track [Page 17] RFC 2911 IPP/1.1: Model and Semantics September 2000

 IPP/1.1 does not specify how the client obtains the client supplied
 URI, but it is RECOMMENDED that a Printer object be registered as an
 entry in a directory service.  End-users and programs can then
 interrogate the directory searching for Printers. Section 16 defines
 a generic schema for Printer object entries in the directory service
 and describes how the entry acts as a bridge to the actual IPP
 Printer object.  The entry in the directory that represents the IPP
 Printer object includes the possibly many URIs for that Printer
 object as values in one its attributes.
 When a client submits a create request to the Printer object, the
 Printer object validates the request and creates a new Job object.
 The Printer object assigns the new Job object a URI which is stored
 in the "job-uri" Job attribute.  This URI is then used by clients as
 the target for subsequent Job operations.  The Printer object
 generates a Job URI based on its configured security policy and the
 URI used by the client in the create request.
 For example, consider a Printer object that supports both a
 communication channel secured by the use of SSL3 (using HTTP over
 SSL3 with an "https" schemed URI) and another open communication
 channel that is not secured with SSL3 (using a simple "http" schemed
 URI).  If a client were to submit a job using the secure URI, the
 Printer object would assign the new Job object a secure URI as well.
 If a client were to submit a job using the open-channel URI, the
 Printer would assign the new Job object an open-channel URI.
 In addition, the Printer object also populates the Job object's
 "job-printer-uri" attribute.  This is a reference back to the Printer
 object that created the Job object.  If a client only has access to a
 Job object's "job-uri" identifier, the client can query the Job's
 "job-printer-uri" attribute in order to determine which Printer
 object created the Job object.  If the Printer object supports more
 than one URI, the Printer object picks the one URI supplied by the
 client when creating the job to build the value for and to populate
 the Job's "job-printer-uri" attribute.
 Allowing Job objects to have URIs allows for flexibility and
 scalability.  For example, in some implementations, the Printer
 object might create Jobs that are processed in the same local
 environment as the Printer object itself.  In this case, the Job URI
 might just be a composition of the Printer's URI and some unique
 component for the Job object, such as the unique 32-bit positive
 integer mentioned later in this paragraph.  In other implementations,
 the Printer object might be a central clearing-house for validating
 all Job object creation requests, but the Job object itself might be
 created in some environment that is remote from the Printer object.
 In this case, the Job object's URI may have no physical-location

Hastings, et al. Standards Track [Page 18] RFC 2911 IPP/1.1: Model and Semantics September 2000

 relationship at all to the Printer object's URI.  Again, the fact
 that Job objects have URIs allows for flexibility and scalability,
 however, many existing printing systems have local models or
 interface constraints that force print jobs to be identified using
 only a 32-bit positive integer rather than an independent URI.  This
 numeric Job ID is only unique within the context of the Printer
 object to which the create request was originally submitted.
 Therefore, in order to allow both types of client access to IPP Job
 objects (either by Job URI or by numeric Job ID), when the Printer
 object successfully processes a create request and creates a new Job
 object, the Printer object MUST generate both a Job URI and a Job ID.
 The Job ID (stored in the "job-id" attribute) only has meaning in the
 context of the Printer object to which the create request was
 originally submitted. This requirement to support both Job URIs and
 Job IDs allows all types of clients to access Printer objects and Job
 objects no matter the local constraints imposed on the client
 implementation.
 In addition to identifiers, Printer objects and Job objects have
 names ("printer-name" and "job-name").  An object name NEED NOT be
 unique across all instances of all objects. A Printer object's name
 is chosen and set by an administrator through some mechanism outside
 the scope of this IPP/1.1 document.  A Job object's name is
 optionally chosen and supplied by the IPP client submitting the job.
 If the client does not supply a Job object name, the Printer object
 generates a name for the new Job object.  In all cases, the name only
 has local meaning.
 To summarize:
  1. Each Printer object is identified with one or more URIs. The

Printer's "printer-uri-supported" attribute contains the URI(s).

  1. The Printer object's "uri-security-supported" attribute

identifies the communication channel security protocols that may

      or may not have been configured for the various Printer object
      URIs (e.g., 'tls' or 'none').
    - The Printer object's "uri-authentication-supported" attribute
      identifies the authentication mechanisms that may or may not
      have been configured for the various Printer object URIs (e.g.,
      'digest' or 'none').
    - Each Job object is identified with a Job URI.  The Job's "job-
      uri" attribute contains the URI.
    - Each Job object is also identified with Job ID which is a 32-
      bit, positive integer.  The Job's "job-id" attribute contains
      the Job ID.  The Job ID is only unique within the context of the
      Printer object  which created the Job object.

Hastings, et al. Standards Track [Page 19] RFC 2911 IPP/1.1: Model and Semantics September 2000

  1. Each Job object has a "job-printer-uri" attribute which contains

the URI of the Printer object that was used to create the Job

      object.  This attribute is used to determine the Printer object
      that created a Job object when given only the URI for the Job
      object.  This linkage is necessary to determine the languages,
      charsets, and operations which are supported on that Job (the
      basis for such support comes from the creating Printer object).
    - Each Printer object has a name (which is not necessarily
      unique).  The administrator chooses and sets this name through
      some mechanism outside the scope of this IPP/1.1 document.  The
      Printer object's "printer-name" attribute contains the name.
    - Each Job object has a name (which is not necessarily unique).
      The client optionally supplies this name in the create request.
      If the client does not supply this name, the Printer object
      generates a name for the Job object. The Job object's "job-name"
      attribute contains the name.

3. IPP Operations

 IPP objects support operations.  An operation consists of a request
 and a response.  When a client communicates with an IPP object, the
 client issues an operation request to the URI for that object.
 Operation requests and responses have parameters that identify the
 operation.  Operations also have attributes that affect the run-time
 characteristics of the operation (the intended target, localization
 information, etc.).  These operation-specific attributes are called
 operation attributes (as compared to object attributes such as
 Printer object attributes or Job object attributes).  Each request
 carries along with it any operation attributes, object attributes,
 and/or document data required to perform the operation.  Each request
 requires a response from the object.  Each response indicates success
 or failure of the operation with a status code as a response
 parameter.  The response contains any operation attributes, object
 attributes, and/or status messages generated during the execution of
 the operation request.
 This section describes the semantics of the IPP operations, both
 requests and responses, in terms of the parameters, attributes, and
 other data associated with each operation.

Hastings, et al. Standards Track [Page 20] RFC 2911 IPP/1.1: Model and Semantics September 2000

 The IPP/1.1 Printer operations are:
   Print-Job (section 3.2.1)
   Print-URI (section 3.2.2)
   Validate-Job (section 3.2.3)
   Create-Job (section 3.2.4)
   Get-Printer-Attributes (section 3.2.5)
   Get-Jobs (section 3.2.6)
   Pause-Printer (section 3.3.5)
   Resume-Printer (section 3.3.6)
   Purge-Jobs (section 3.3.7)
 The Job operations are:
   Send-Document (section 3.3.1)
   Send-URI (section 3.3.2)
   Cancel-Job (section 3.3.3)
   Get-Job-Attributes (section 3.3.4)
   Hold-Job (section 3.3.5)
   Release-Job (section 3.3.6)
   Restart-Job (section 3.3.7)
 The Send-Document and Send-URI Job operations are used to add a new
 document to an existing multi-document Job object created using the
 Create-Job operation.

3.1 Common Semantics

 All IPP operations require some common parameters and operation
 attributes.  These common elements and their semantic characteristics
 are defined and described in more detail in the following sections.

3.1.1 Required Parameters

 Every operation request contains the following REQUIRED parameters:
  1. a "version-number",
  2. an "operation-id",
  3. a "request-id", and
  4. the attributes that are REQUIRED for that type of request.
 Every operation response contains the following REQUIRED parameters:
  1. a "version-number",
  2. a "status-code",
  3. the "request-id" that was supplied in the corresponding request,

and

  1. the attributes that are REQUIRED for that type of response.

Hastings, et al. Standards Track [Page 21] RFC 2911 IPP/1.1: Model and Semantics September 2000

 The "Encoding and Transport" document [RFC2910] defines special rules
 for the encoding of these parameters.  All other operation elements
 are represented using the more generic encoding rules for attributes
 and groups of attributes.

3.1.2 Operation IDs and Request IDs

 Each IPP operation request includes an identifying "operation-id"
 value.  Valid values are defined in the "operations-supported"
 Printer attribute section (see section 4.4.15).  The client specifies
 which operation is being requested by supplying the correct
 "operation-id" value.
 In addition, every invocation of an operation is identified by a
 "request-id" value. For each request, the client chooses the
 "request-id" which MUST be an integer (possibly unique depending on
 client requirements) in the range from 1 to 2**31 - 1 (inclusive).
 This "request-id" allows clients to manage multiple outstanding
 requests. The receiving IPP object copies all 32-bits of the client-
 supplied "request-id" attribute into the response so that the client
 can match the response with the correct outstanding request, even if
 the "request-id" is out of range.  If the request is terminated
 before the complete "request-id" is received, the IPP object rejects
 the request and returns a response with a "request-id" of 0.
 Note: In some cases, the transport protocol underneath IPP might be a
 connection oriented protocol that would make it impossible for a
 client to receive responses in any order other than the order in
 which the corresponding requests were sent.  In such cases, the
 "request-id" attribute would not be essential for correct protocol
 operation.  However, in other mappings, the operation responses can
 come back in any order.  In these cases, the "request-id" would be
 essential.

3.1.3 Attributes

 Operation requests and responses are both composed of groups of
 attributes and/or document data.  The attributes groups are:
  1. Operation Attributes: These attributes are passed in the

operation and affect the IPP object's behavior while processing

      the operation request and may affect other attributes or groups
      of attributes.  Some operation attributes describe the document
      data associated with the print job and are associated with new
      Job objects, however most operation attributes do not persist
      beyond the life of the operation.  The description of each
      operation attribute includes conformance statements indicating
      which operation attributes are REQUIRED and which are OPTIONAL

Hastings, et al. Standards Track [Page 22] RFC 2911 IPP/1.1: Model and Semantics September 2000

      for an IPP object to support and which attributes a client MUST
      supply in a request and an IPP object MUST supply in a response.
    - Job Template Attributes: These attributes affect the processing
      of a job.  A client OPTIONALLY supplies Job Template Attributes
      in a create request, and the receiving object MUST be prepared
      to receive all supported attributes.  The Job object can later
      be queried to find out what Job Template attributes were
      originally requested in the create request, and such attributes
      are returned in the response as Job Object Attributes.  The
      Printer object can be queried about its Job Template attributes
      to find out what type of job processing capabilities are
      supported and/or what the default job processing behaviors are,
      though such attributes are returned in the response as Printer
      Object Attributes.  The "ipp-attribute-fidelity" operation
      attribute affects processing of all client-supplied Job Template
      attributes (see sections 3.2.1.2 and 15 for a full description
      of "ipp-attribute-fidelity" and its relationship to other
      attributes).
    - Job Object Attributes: These attributes are returned in response
      to a query operation directed at a Job object.
    - Printer Object Attributes: These attributes are returned in
      response to a query operation directed at a Printer object.
    - Unsupported Attributes: In a create request, the client supplies
      a set of Operation and Job Template attributes.  If any of these
      attributes or their values is unsupported by the Printer object,
      the Printer object returns the set of unsupported attributes in
      the response.  Sections 3.1.7, 3.2.1.2, and  15 give a full
      description of how Job Template attributes supplied by the
      client in a create request are processed by the Printer object
      and how unsupported attributes are returned to the client.
      Because of extensibility, any IPP object might receive a request
      that contains new or unknown attributes or values for which it
      has no support. In such cases, the IPP object processes what it
      can and returns the unsupported attributes in the response. The
      Unsupported Attribute group is defined for all operation
      responses for returning unsupported attributes that the client
      supplied in the request.
 Later in this section, each operation is formally defined by
 identifying the allowed and expected groups of attributes for each
 request and response.  The model identifies a specific order for each
 group in each request or response, but the attributes within each
 group may be in any order, unless specified otherwise.
 The attributes within a group MUST be unique; if an attribute with
 the same name occurs more than once, the group is mal-formed.
 Clients MUST NOT submit such malformed requests and Printers MUST NOT
 return such malformed responses.  If such a malformed request is

Hastings, et al. Standards Track [Page 23] RFC 2911 IPP/1.1: Model and Semantics September 2000

 submitted to a Printer, the Printer MUST either (1) reject the
 request with the 'client-error-bad-request' status code (see section
 13.1.4.1) or (2) process the request normally after selecting only
 one of the attribute instances, depending on implementation.  Which
 attribute is selected when there are duplicate attributes depends on
 implementation.  The IPP Printer MUST NOT use the values from more
 than one such duplicate attribute instance.
 Each attribute definition includes the attribute's name followed by
 the name of its attribute syntax(es) in parenthesizes.  In addition,
 each 'integer' attribute is followed by the allowed range in
 parentheses, (m:n), for values of that attribute.  Each 'text' or
 'name' attribute is followed by the maximum size in octets in
 parentheses, (size), for values of that attribute. For more details
 on attribute syntax notation, see the descriptions of these
 attributes syntaxes in section 4.1.
 Note: Document data included in the operation is not strictly an
 attribute, but it is treated as a special attribute group for
 ordering purposes.  The only operations that support supplying the
 document data within an operation request are Print-Job and Send-
 Document.  There are no operation responses that include document
 data.
 Some operations are REQUIRED for IPP objects to support; the others
 are OPTIONAL (see section 5.2.2).  Therefore, before using an
 OPTIONAL operation, a client SHOULD first use the REQUIRED Get-
 Printer-Attributes operation to query the Printer's "operations-
 supported" attribute in order to determine which OPTIONAL Printer and
 Job operations are actually supported.  The client SHOULD NOT use an
 OPTIONAL operation that is not supported.  When an IPP object
 receives a request to perform an operation it does not support, it
 returns the 'server-error-operation-not-supported' status code (see
 section 13.1.5.2).  An IPP object is non-conformant if it does not
 support a REQUIRED operation.

3.1.4 Character Set and Natural Language Operation Attributes

 Some Job and Printer attributes have values that are text strings and
 names intended for human understanding rather than machine
 understanding (see the 'text' and 'name' attribute syntax
 descriptions in section 4.1).  The following sections describe two
 special Operation Attributes called "attributes-charset" and
 "attributes-natural-language".  These attributes are always part of
 the Operation Attributes group.  For most attribute groups, the order
 of the attributes within the group is not important.  However, for
 these two attributes within the Operation Attributes group, the order
 is critical.  The "attributes-charset" attribute MUST be the first

Hastings, et al. Standards Track [Page 24] RFC 2911 IPP/1.1: Model and Semantics September 2000

 attribute in the group and the "attributes-natural-language"
 attribute MUST be the second attribute in the group.  In other words,
 these attributes MUST be supplied in every IPP request and response,
 they MUST come first in the group, and MUST come in the specified
 order.  For job creation operations, the IPP Printer implementation
 saves these two attributes with the new Job object as Job Description
 attributes.  For the sake of brevity in this document, these
 operation attribute descriptions are not repeated with every
 operation request and response, but have a reference back to this
 section instead.

3.1.4.1 Request Operation Attributes

 The client MUST supply and the Printer object MUST support the
 following REQUIRED operation attributes in every IPP/1.1 operation
 request:
    "attributes-charset" (charset):
       This operation attribute identifies the charset (coded
       character set and encoding method) used by any 'text' and
       'name' attributes that the client is supplying in this request.
       It also identifies the charset that the Printer object MUST use
       (if supported) for all 'text' and 'name' attributes and status
       messages that the Printer object returns in the response to
       this request. See Sections 4.1.1 and 4.1.2 for the definition
       of the 'text' and 'name' attribute syntaxes.
       All clients and IPP objects MUST support the 'utf-8' charset
       [RFC2279] and MAY support additional charsets provided that
       they are registered with IANA [IANA-CS].  If the Printer object
       does not support the client supplied charset value, the Printer
       object MUST reject the request, set the "attributes-charset" to
       'utf-8' in the response, and return the 'client-error-charset-
       not-supported' status code and any 'text' or 'name' attributes
       using the 'utf-8' charset. The Printer NEED NOT return any
       attributes in the Unsupported Attributes Group (See sections
       3.1.7 and 3.2.1.2).  The Printer object MUST indicate the
       charset(s) supported as the values of the "charset-supported"
       Printer attribute (see Section 4.4.18), so that the client can
       query to determine which charset(s) are supported.
       Note to client implementers: Since IPP objects are only
       required to support the 'utf-8' charset, in order to maximize
       interoperability with multiple IPP object implementations, a
       client may want to supply 'utf-8' in the "attributes-charset"
       operation attribute, even though the client is only passing and
       able to present a simpler charset, such as US-ASCII [ASCII] or
       ISO-8859-1 [ISO8859-1].  Then the client will have to filter

Hastings, et al. Standards Track [Page 25] RFC 2911 IPP/1.1: Model and Semantics September 2000

       out (or charset convert) those characters that are returned in
       the response that it cannot present to its user.  On the other
       hand, if both the client and the IPP objects also support a
       charset in common besides utf-8, the client may want to use
       that charset in order to avoid charset conversion or data loss.
       See the 'charset' attribute syntax description in Section 4.1.7
       for the syntax and semantic interpretation of the values of
       this attribute and for example values.
    "attributes-natural-language" (naturalLanguage):
       This operation attribute identifies the natural language used
       by any 'text' and 'name' attributes that the client is
       supplying in this request.  This attribute also identifies the
       natural language that the Printer object SHOULD use for all
       'text' and 'name' attributes and status messages that the
       Printer object returns in the response to this request.  See
       the 'naturalLanguage' attribute syntax description in section
       4.1.8 for the syntax and semantic interpretation of the values
       of this attribute and for example values.
       There are no REQUIRED natural languages required for the
       Printer object to support.  However, the Printer object's
       "generated-natural-language-supported" attribute identifies the
       natural languages supported by the Printer object and any
       contained Job objects for all text strings generated by the IPP
       object.  A client MAY query this attribute to determine which
       natural language(s) are supported for generated messages.
       For any of the attributes for which the Printer object
       generates text, i.e., for the "job-state-message", "printer-
       state-message", and status messages (see Section 3.1.6), the
       Printer object MUST be able to generate these text strings in
       any of its supported natural languages.  If the client requests
       a natural language that is not supported, the Printer object
       MUST return these generated messages in the Printer's
       configured natural language as specified by the Printer's
       "natural-language-configured" attribute" (see Section 4.4.19).
       For other 'text' and 'name' attributes supplied by the client,
       authentication system, operator, system administrator, or
       manufacturer (i.e., for "job-originating-user-name", "printer-
       name" (name), "printer-location" (text), "printer-info" (text),
       and "printer-make-and-model" (text)), the Printer object is
       only required to support the configured natural language of the

Hastings, et al. Standards Track [Page 26] RFC 2911 IPP/1.1: Model and Semantics September 2000

       Printer identified by the Printer object's "natural-language-
       configured" attribute, though support of additional natural
       languages for these attributes is permitted.
       For any 'text' or 'name' attribute in the request that is in a
       different natural language than the value supplied in the
       "attributes-natural-language" operation attribute, the client
       MUST use the Natural Language Override mechanism (see sections
       4.1.1.2 and 4.1.2.2) for each such attribute value supplied.
       The client MAY use the Natural Language Override mechanism
       redundantly, i.e., use it even when the value is in the same
       natural language as the value supplied in the "attributes-
       natural-language" operation attribute of the request.
       The IPP object MUST accept any natural language and any Natural
       Language Override, whether the IPP object supports that natural
       language or not (and independent of the value of the "ipp-
       attribute-fidelity" Operation attribute).  That is the IPP
       object accepts all client supplied values no matter what the
       values are in the Printer object's "generated-natural-
       language-supported" attribute.  That attribute, "generated-
       natural-language-supported", only applies to generated
       messages, not client supplied messages.  The IPP object MUST
       remember that natural language for all client-supplied
       attributes, and when returning those attributes in response to
       a query, the IPP object MUST indicate that natural language.
       Each value whose attribute syntax type is 'text' or 'name' (see
       sections 4.1.1 and 4.1.2) has an Associated Natural-Language.
       This document does not specify how this association is stored
       in a Printer or Job object.  When such a value is encoded in a
       request or response, the natural language is either implicit or
       explicit:
  1. In the implicit case, the value contains only the text/name

value, and the language is specified by the "attributes-

         natural-language" operation attribute in the request or
         response (see sections 4.1.1.1 textWithoutLanguage and
         4.1.2.1 nameWithoutLanguage).
  1. In the explicit case (also known as the Natural-Language

Override case), the value contains both the language and the

         text/name value (see sections 4.1.1.2 textWithLanguage and
         4.1.2.2 nameWithLanguage).
       For example, the "job-name" attribute MAY be supplied by the
       client in a create request.  The text value for this attribute
       will be in the natural language identified by the "attribute-

Hastings, et al. Standards Track [Page 27] RFC 2911 IPP/1.1: Model and Semantics September 2000

       natural-language" attribute, or if different, as identified by
       the Natural Language Override mechanism.  If supplied, the IPP
       object will use the value of the "job-name" attribute to
       populate the Job object's "job-name" attribute.  Whenever any
       client queries the Job object's "job-name" attribute, the IPP
       object returns the attribute as stored and uses the Natural
       Language Override mechanism to specify the natural language, if
       it is different from that reported in the "attributes-natural-
       language" operation attribute of the response.  The IPP object
       MAY use the Natural Language Override mechanism redundantly,
       i.e., use it even when the value is in the same natural
       language as the value supplied in the "attributes-natural-
       language" operation attribute of the response.
       An IPP object MUST NOT reject a request based on a supplied
       natural language in an "attributes-natural-language" Operation
       attribute or in any attribute that uses the Natural Language
       Override.
 Clients SHOULD NOT supply 'text' or 'name' attributes that use an
 illegal combination of natural language and charset.  For example,
 suppose a Printer object supports charsets 'utf-8', 'iso-8859-1', and
 'iso-8859-7'.  Suppose also, that it supports natural languages 'en'
 (English), 'fr' (French), and 'el' (Greek).  Although the Printer
 object supports the charset 'iso-8859-1' and natural language 'el',
 it probably does not support the combination of Greek text strings
 using the 'iso-8859-1' charset.  The Printer object handles this
 apparent incompatibility differently depending on the context in
 which it occurs:
  1. In a create request: If the client supplies a text or name

attribute (for example, the "job-name" operation attribute) that

      uses an apparently incompatible combination, it is a client
      choice that does not affect the Printer object or its correct
      operation.  Therefore, the Printer object simply accepts the
      client supplied value, stores it with the Job object, and
      responds back with the same combination whenever the client (or
      any client) queries for that attribute.
    - In a query-type operation, like Get-Printer-Attributes: If the
      client requests an apparently incompatible combination, the
      Printer object responds (as described in section 3.1.4.2) using
      the Printer's configured natural language rather than the
      natural language requested by the client.
 In either case, the Printer object does not reject the request
 because of the apparent incompatibility.  The potential incompatible
 combination of charset and natural language can occur either at the
 global operation level or at the Natural Language Override

Hastings, et al. Standards Track [Page 28] RFC 2911 IPP/1.1: Model and Semantics September 2000

 attribute-by-attribute level.  In addition, since the response always
 includes explicit charset and natural language information, there is
 never any question or ambiguity in how the client interprets the
 response.

3.1.4.2 Response Operation Attributes

 The Printer object MUST supply and the client MUST support the
 following REQUIRED operation attributes in every IPP/1.1 operation
 response:
    "attributes-charset" (charset):
       This operation attribute identifies the charset used by any
       'text' and 'name' attributes that the Printer object is
       returning in this response.  The value in this response MUST be
       the same value as the "attributes-charset" operation attribute
       supplied by the client in the request.  If this is not possible
       (i.e., the charset requested is not supported), the request
       would have been rejected.  See "attributes-charset" described
       in Section 3.1.4.1 above.
       If the Printer object supports more than just the 'utf-8'
       charset, the Printer object MUST be able to code convert
       between each of the charsets supported on a highest fidelity
       possible basis in order to return the 'text' and 'name'
       attributes in the charset requested by the client.  However,
       some information loss MAY occur during the charset conversion
       depending on the charsets involved.  For example, the Printer
       object may convert from a UTF-8 'a' to a US-ASCII 'a' (with no
       loss of information), from an ISO Latin 1 CAPITAL LETTER A WITH
       ACUTE ACCENT to US-ASCII 'A' (losing the accent), or from a
       UTF-8 Japanese Kanji character to some ISO Latin 1 error
       character indication such as '?', decimal code equivalent, or
       to the absence of a character, depending on implementation.
       Whether an implementation that supports more than one charset
       stores the data in the charset supplied by the client or code
       converts to one of the other supported charsets, depends on
       implementation.  The strategy should try to minimize loss of
       information during code conversion.  On each response, such an
       implementation converts from its internal charset to that
       requested.
    "attributes-natural-language" (naturalLanguage):
       This operation attribute identifies the natural language used
       by any 'text' and 'name' attributes that the IPP object is
       returning in this response.  Unlike the "attributes-charset"
       operation attribute, the IPP object NEED NOT return the same

Hastings, et al. Standards Track [Page 29] RFC 2911 IPP/1.1: Model and Semantics September 2000

       value as that supplied by the client in the request.  The IPP
       object MAY return the natural language of the Job object or the
       Printer's configured natural language as identified by the
       Printer object's "natural-language-configured" attribute,
       rather than the natural language supplied by the client.  For
       any 'text' or 'name' attribute or status message in the
       response that is in a different natural language than the value
       returned in the "attributes-natural-language" operation
       attribute, the IPP object MUST use the Natural Language
       Override mechanism (see sections 4.1.1.2 and 4.1.2.2) on each
       attribute value returned.  The IPP object MAY use the Natural
       Language Override mechanism redundantly, i.e., use it even when
       the value is in the same natural language as the value supplied
       in the "attributes-natural-language" operation attribute of the
       response.

3.1.5 Operation Targets

 All IPP operations are directed at IPP objects.  For Printer
 operations, the operation is always directed at a Printer object
 using one of its URIs (i.e., one of the values in the Printer
 object's "printer-uri-supported" attribute).  Even if the Printer
 object supports more than one URI, the client supplies only one URI
 as the target of the operation.  The client identifies the target
 object by supplying the correct URI in the "printer-uri (uri)"
 operation attribute.
 For Job operations, the operation is directed at either:
  1. The Job object itself using the Job object's URI. In this case,

the client identifies the target object by supplying the correct

      URI in the "job-uri (uri)" operation attribute.
    - The Printer object that created the Job object using both the
      Printer objects URI and the Job object's Job ID.  Since the
      Printer object that created the Job object generated the Job ID,
      it MUST be able to correctly associate the client supplied Job
      ID with the correct Job object.  The client supplies the Printer
      object's URI in the "printer-uri (uri)" operation attribute and
      the Job object's Job ID in the "job-id (integer(1:MAX))"
      operation attribute.
 If the operation is directed at the Job object directly using the Job
 object's URI, the client MUST NOT include the redundant "job-id"
 operation attribute.

Hastings, et al. Standards Track [Page 30] RFC 2911 IPP/1.1: Model and Semantics September 2000

 The operation target attributes are REQUIRED operation attributes
 that MUST be included in every operation request.  Like the charset
 and natural language attributes (see section 3.1.4), the operation
 target attributes are specially ordered operation attributes.  In all
 cases, the operation target attributes immediately follow the
 "attributes-charset" and "attributes-natural-language" attributes
 within the operation attribute group, however the specific ordering
 rules are:
  1. In the case where there is only one operation target attribute

(i.e., either only the "printer-uri" attribute or only the

      "job-uri" attribute), that attribute MUST be the third attribute
      in the operation attributes group.
    - In the case where Job operations use two operation target
      attributes (i.e., the "printer-uri" and "job-id" attributes),
      the "printer-uri" attribute MUST be the third attribute and the
      "job-id" attribute MUST be the fourth attribute.
 In all cases, the target URIs contained within the body of IPP
 operation requests and responses must be in absolute format rather
 than relative format (a relative URL identifies a resource with the
 scope of the HTTP server, but does not include scheme, host or port).
 The following rules apply to the use of port numbers in URIs that
 identify IPP objects:
    1. If the URI scheme allows the port number to be explicitly
       included in the URI string, and a port number is specified
       within the URI, then that port number MUST be used by the
       client to contact the IPP object.
    2. If the URI scheme allows the port number to be explicitly
       included in the URI string, and a port number is not specified
       within the URI, then default port number implied by that URI
       scheme MUST be used by the client to contact the IPP object.
    3. If the URI scheme does not allow an explicit port number to be
       specified within the URI, then the default port number implied
       by that URI MUST be used by the client to contact the IPP
       object.
 Note: The IPP "Encoding and Transport document [RFC2910] shows a
 mapping of IPP onto HTTP/1.1 [RFC2616] and defines a new default port
 number for using IPP over HTTP/1.1.

Hastings, et al. Standards Track [Page 31] RFC 2911 IPP/1.1: Model and Semantics September 2000

3.1.6 Operation Response Status Codes and Status Messages

 Every operation response includes a REQUIRED "status-code" parameter
 and an OPTIONAL "status-message" operation attribute, and an OPTIONAL
 "detailed-status-message" operation attribute.  The Print-URI and
 Send-URI response MAY include an OPTIONAL "document-access-error"
 operation attribute.

3.1.6.1 "status-code" (type2 enum)

 The REQUIRED "status-code" parameter provides information on the
 processing of a request.
 The status code is intended for use by automata.  A client
 implementation of IPP SHOULD convert status code values into any
 localized message that has semantic meaning to the end user.
 The "status-code" value is a numeric value that has semantic meaning.
 The "status-code" syntax is similar to a "type2 enum" (see section
 4.1 on "Attribute Syntaxes") except that values can range only from
 0x0000 to 0x7FFF.  Section 13 describes the status codes, assigns the
 numeric values, and suggests a corresponding status message for each
 status code for use by the client when the user's natural language is
 English.
 If the Printer performs an operation with no errors and it encounters
 no problems, it MUST return the status code 'successful-ok' in the
 response.  See section 13.
 If the client supplies unsupported values for the following
 parameters or Operation attributes, the Printer object MUST reject
 the operation, NEED NOT return the unsupported attribute value in the
 Unsupported Attributes group, and MUST return the indicated status
 code:
      Parameter/Attribute                 Status code
      version-number      server-error-version-not-supported
      operation-id        server-error-operation-not-supported
      attributes-charset  client-error-charset-not-supported
      compression         client-error-compression-not-supported
      document-format     client-error-document-format-not-supported
      document-uri        client-error-uri-scheme-not-supported,
                           client-error-document-access-error
 If the client supplies unsupported values for other attributes, or
 unsupported attributes, the Printer returns the status code defined
 in section 3.1.7 on Unsupported Attributes.

Hastings, et al. Standards Track [Page 32] RFC 2911 IPP/1.1: Model and Semantics September 2000

3.1.6.2 "status-message" (text(255))

 The OPTIONAL "status-message" operation attribute provides a short
 textual description of the status of the operation.  The "status-
 message" attribute's syntax is "text(255)", so the maximum length is
 255 octets (see section 4.1.1).  The status message is intended for
 the human end user.  If a response does include a "status-message"
 attribute, an IPP client NEED NOT examine or display the messages,
 however it SHOULD do so in some implementation specific manner.  The
 "status-message" is especially useful for a later version of a
 Printer object to return as supplemental information for the human
 user to accompany a status code that an earlier version of a client
 might not understand.
 If the Printer object supports the "status-message" operation
 attribute, the Printer object MUST be able to generate this message
 in any of the natural languages identified by the Printer object's
 "generated-natural-language-supported" attribute (see the
 "attributes-natural-language" operation attribute specified in
 section 3.1.4.1.  Section 13 suggests the text for the status message
 returned by the Printer for use with the English natural language.
 As described in section 3.1.4.1 for any returned 'text' attribute, if
 there is a choice for generating this message, the Printer object
 uses the natural language indicated by the value of the "attributes-
 natural-language" in the client request if supported, otherwise the
 Printer object uses the value in the Printer object's own "natural-
 language-configured" attribute.
 If the Printer object supports the "status-message" operation
 attribute, it SHOULD use the REQUIRED 'utf-8' charset to return a
 status message for the following error status codes (see section 13):
 'client-error-bad-request', 'client-error-charset-not-supported',
 'server-error-internal-error', 'server-error-operation-not-
 supported', and 'server-error-version-not-supported'.  In this case,
 it MUST set the value of the "attributes-charset" operation attribute
 to 'utf-8' in the error response.

3.1.6.3 "detailed-status-message" (text(MAX))

 The OPTIONAL "detailed-status-message" operation attribute provides
 additional more detailed technical and implementation-specific
 information about the operation.  The "detailed-status-message"
 attribute's syntax is "text(MAX)", so the maximum length is 1023
 octets (see section 4.1.1).    If the Printer objects supports the
 "detailed-status-message" operation attribute, the Printer NEED NOT
 localize the message, since it is intended for use by the system
 administrator or other experienced technical persons.  Localization

Hastings, et al. Standards Track [Page 33] RFC 2911 IPP/1.1: Model and Semantics September 2000

 might obscure the technical meaning of such messages.  Clients MUST
 NOT attempt to parse the value of this attribute.  See the
 "document-access-error" operation attribute (section 3.1.6.4) for
 additional errors that a program can process.

3.1.6.4 "document-access-error" (text(MAX))

 This OPTIONAL operation attribute provides additional information
 about any document access errors encountered by the Printer before it
 returned a response to the Print-URI (section 3.2.2) or Send-URI
 (section 3.3.1) operation.  For errors in the protocol identified by
 the URI scheme in the "document-uri" operation attribute, such as
 'http:' or 'ftp:', the error code is returned in parentheses,
 followed by the URI.  For example:
    (404) http://ftp.pwg.org/pub/pwg/ipp/new_MOD/ipp-model-v11.pdf
 Most Internet protocols use decimal error codes (unlike IPP), so the
 ASCII error code representation is in decimal.

3.1.7 Unsupported Attributes

 The Unsupported Attributes group contains attributes that are not
 supported by the operation. This group is primarily for the job
 creation operations, but all operations can return this group.
 A Printer object MUST include an Unsupported Attributes group in a
 response if the status code is one of the following:  'successful-
 ok-ignored-or-substituted-attributes', 'successful-ok-conflicting-
 attributes', 'client-error-attributes-or-values-not-supported' or
 'client-error-conflicting-attributes'.
 If the status code is one of the four specified in the preceding
 paragraph, the Unsupported Attributes group MUST contain all of those
 attributes and only those attributes that are:
    a. an Operation or Job Template attribute supplied in the request,
       and
    b. unsupported by the printer. See below for details on the three
       categories "unsupported" attributes.
 If the status code is one of those in the table in section 3.1.6.1,
 the Unsupported Attributes group NEED NOT contain the unsupported
 parameter or attribute indicated in that table.

Hastings, et al. Standards Track [Page 34] RFC 2911 IPP/1.1: Model and Semantics September 2000

 If the Printer object is not returning any Unsupported Attributes in
 the response, the Printer object SHOULD omit Group 2 rather than
 sending an empty group.  However, a client MUST be able to accept an
 empty group.
 Unsupported attributes fall into three categories:
    1. The Printer object does not support the supplied attribute (no
       matter what the attribute syntax or value).
    2. The Printer object does support the attribute, but does not
       support some or all of the particular attribute syntaxes or
       values supplied by the client (i.e., the Printer object does
       not have those attribute syntaxes or values in its
       corresponding "xxx-supported" attribute).
    3. The Printer object does support the attributes and values
       supplied, but the particular values are in conflict with one
       another, because they violate a constraint, such as not being
       able to staple transparencies.
 In the case of an unsupported attribute name, the Printer object
 returns the client-supplied attribute with a substituted value of
 'unsupported'.  This value's syntax type is "out-of-band" and its
 encoding is defined by special rules for "out-of-band" values in the
 "Encoding and Transport" document [RFC2910].   Its value indicates no
 support for the attribute itself (see the beginning of section 4.1).
 In the case of a supported attribute with one or more unsupported
 attribute syntaxes or values, the Printer object simply returns the
 client-supplied attribute with the unsupported attribute syntaxes or
 values as supplied by the client.  This indicates support for the
 attribute, but no support for that particular attribute syntax or
 value.  If the client supplies a multi-valued attribute with more
 than one value and the Printer object supports the attribute but only
 supports a subset of the client-supplied attribute syntaxes or
 values, the Printer object
 MUST return only those attribute syntaxes or values that are
 unsupported.
 In the case of two (or more) supported attribute values that are in
 conflict with one another (although each is supported independently,
 the values conflict when requested together within the same job), the
 Printer object MUST return all the values that it ignores or
 substitutes to resolve the conflict, but not any of the values that

Hastings, et al. Standards Track [Page 35] RFC 2911 IPP/1.1: Model and Semantics September 2000

 it is still using.  The choice for exactly how to resolve the
 conflict is implementation dependent.  See sections 3.2.1.2 and 15.
 See The Implementer's Guide [IPP-IIG] for an example.

3.1.8 Versions

 Each operation request and response carries with it a "version-
 number" parameter.  Each value of the "version-number" is in the form
 "X.Y" where X is the major version number and Y is the minor version
 number.  By including a version number in the client request, it
 allows the client  to identify which version of IPP it is interested
 in using, i.e., the version whose conformance requirements the client
 may be depending upon the Printer to meet.
 If the IPP object does not support that major version number supplied
 by the client, i.e., the major version field of the "version-number"
 parameter does not match any of the values of the Printer's "ipp-
 versions-supported" (see section 4.4.14), the object MUST respond
 with a status code of 'server-error-version-not-supported' along with
 the closest version number that is supported (see section 13.1.5.4).
 If the major version number is supported, but the minor version
 number is not, the IPP object SHOULD accept and attempt to perform
 the request (or reject the request if the operation is not
 supported), else it rejects the request and returns the 'server-
 error-version-not-supported' status code.  In all cases, the IPP
 object MUST return the "version-number" that it supports that is
 closest to the version number supplied by the client in the request.
 There is no version negotiation per se.  However, if after receiving
 a 'server-error-version-not-supported' status code from an IPP
 object, a client SHOULD try again with a different version number. A
 client MAY also determine the versions supported either from a
 directory that conforms to Appendix E (see section 16) or by querying
 the Printer object's "ipp-versions-supported" attribute (see section
 4.4.14) to determine which versions are supported.
 An IPP object implementation MUST support version '1.1', i.e., meet
 the conformance requirements for IPP/1.1 as specified in this
 document and [RFC2910].  It is recommended that IPP object
 implementations accept any request with the major version '1' (or
 reject the request if the operation is not supported).
 There is only one notion of "version number" that covers both IPP
 Model and IPP Protocol changes. Thus the version number MUST change
 when introducing a new version of the Model and Semantics document
 (this document) or a new version of the "Encoding and Transport"
 document [RFC2910].

Hastings, et al. Standards Track [Page 36] RFC 2911 IPP/1.1: Model and Semantics September 2000

 Changes to the major version number of the Model and Semantics
 document indicate structural or syntactic changes that make it
 impossible for older version of IPP clients and Printer objects to
 correctly parse and correctly process the new or changed attributes,
 operations and responses.  If the major version number changes, the
 minor version numbers is set to zero.  As an example, adding the
 REQUIRED "ipp-attribute-fidelity" attribute to version '1.1' (if it
 had not been part of version '1.0'), would have required a change to
 the major version number, since an IPP/1.0 Printer would not have
 processed a request with the correct semantics that contained the
 "ipp-attribute-fidelity" attribute that it did not know about.  Items
 that might affect the changing of the major version number include
 any changes to the Model and Semantics document (this document) or
 the "Encoding and Transport" document [RFC2910] itself, such as:
  1. reordering of ordered attributes or attribute sets
  2. changes to the syntax of existing attributes
  3. adding REQUIRED (for an IPP object to support) operation

attribute groups

  1. adding values to existing REQUIRED operation attributes
  2. adding REQUIRED operations
 Changes to the minor version number indicate the addition of new
 features, attributes and attribute values that may not be understood
 by all IPP objects, but which can be ignored if not understood.
 Items that might affect the changing of the minor version number
 include any changes to the model objects and attributes but not the
 encoding and transport rules [RFC2910] (except adding attribute
 syntaxes).  Examples of such changes are:
  1. grouping all extensions not included in a previous version into

a new version

  1. adding new attribute values
  2. adding new object attributes
  3. adding OPTIONAL (for an IPP object to support) operation

attributes (i.e., those attributes that an IPP object can ignore

      without confusing clients)
    - adding OPTIONAL (for an IPP object to support) operation
      attribute groups (i.e., those attributes that an IPP object can
      ignore without confusing clients)
    - adding new attribute syntaxes
    - adding OPTIONAL operations
    - changing Job Description attributes or Printer Description
      attributes from OPTIONAL to REQUIRED or vice versa.
    - adding OPTIONAL attribute syntaxes to an existing attribute.
 The encoding of the "version-number" MUST NOT change over any version
 number (either major or minor).  This rule guarantees that all future

Hastings, et al. Standards Track [Page 37] RFC 2911 IPP/1.1: Model and Semantics September 2000

 versions will be backwards compatible with all previous versions (at
 least for checking  the "version-number").  In addition, any protocol
 elements (attributes, error codes, tags, etc.) that are not carried
 forward from one version to the next are deprecated so that they can
 never be reused with new semantics.
 Implementations that support a certain  version NEED NOT support ALL
 previous versions.  As each new  version is defined (through the
 release of a new IPP specification document), that version will
 specify which previous  versions MUST and which versions SHOULD be
 supported in compliant implementations.

3.1.9 Job Creation Operations

 In order to "submit a print job" and create a new Job object, a
 client issues a create request.  A create request is any one of
 following three operation requests:
  1. The Print-Job Request: A client that wants to submit a print job

with only a single document uses the Print-Job operation. The

      operation allows for the client to "push" the document data to
      the Printer object by including the document data in the request
      itself.
  1. The Print-URI Request: A client that wants to submit a print job

with only a single document (where the Printer object "pulls"

      the document data instead of the client "pushing" the data to
      the Printer object) uses the Print-URI operation.   In this
      case, the client includes in the request only a URI reference to
      the document data (not the document data itself).
  1. The Create-Job Request: A client that wants to submit a print

job with multiple documents uses the Create-Job operation. This

      operation is followed by an arbitrary number (one or more) of
      Send-Document and/or Send-URI operations (each creating another
      document for the newly create Job object).  The Send-Document
      operation includes the document data in the request (the client
      "pushes" the document data to the printer), and the Send-URI
      operation includes only a URI reference to the document data in
      the request (the Printer "pulls" the document data from the
      referenced location).  The last Send-Document or Send-URI
      request for a given Job object includes a "last-document"
      operation attribute set to 'true' indicating that this is the
      last request.
 Throughout this model document, the term "create request" is used to
 refer to any of these three operation requests.

Hastings, et al. Standards Track [Page 38] RFC 2911 IPP/1.1: Model and Semantics September 2000

 A Create-Job operation followed by only one Send-Document operation
 is semantically equivalent to a Print-Job operation, however, for
 performance reasons, the client SHOULD use the Print-Job operation
 for all single document jobs.  Also, Print-Job is a REQUIRED
 operation (all implementations MUST support it) whereas Create-Job is
 an OPTIONAL operation, hence some implementations might not support
 it.
 Job submission time is the point in time when a client issues a
 create request.  The initial state of every Job object is the
 'pending', 'pending-held', or 'processing' state (see section 4.3.7).
 When the Printer object begins processing the print job, the Job
 object's state moves to 'processing'.  This is known as job
 processing time.  There are validation checks that must be done at
 job submission time and others that must be performed at job
 processing time.
 At job submission time and at the time a Validate-Job operation is
 received, the Printer MUST do the following:
    1. Process the client supplied attributes and either accept or
       reject the request
    2. Validate the syntax of and support for the scheme of any client
       supplied URI
 At job submission time the Printer object MUST validate whether or
 not the supplied attributes, attribute syntaxes, and values are
 supported by matching them with the Printer object's corresponding
 "xxx-supported" attributes.  See section 3.1.7 for details.  [IPP-
 IIG] presents suggested steps for an IPP object to either accept or
 reject any request and additional steps for processing create
 requests.
 At job submission time the Printer object NEED NOT perform the
 validation checks reserved for job processing time such as:
    1. Validating the document data
    2. Validating the actual contents of any client supplied URI
       (resolve the reference and follow the link to the document
       data)
 At job submission time, these additional job processing time
 validation checks are essentially useless, since they require
 actually parsing and interpreting the document data, are not
 guaranteed to be 100% accurate, and MUST be done, yet again, at job
 processing time.  Also, in the case of a URI, checking for
 availability at job submission time does not guarantee availability

Hastings, et al. Standards Track [Page 39] RFC 2911 IPP/1.1: Model and Semantics September 2000

 at job processing time.  In addition, at job processing time, the
 Printer object might discover any of the following conditions that
 were not detectable at job submission time:
  1. runtime errors in the document data,
  2. nested document data that is in an unsupported format,
  3. the URI reference is no longer valid (i.e., the server hosting

the document might be down), or

  1. any other job processing error
 At job submission time, a Printer object, especially a non-spooling
 Printer, MAY accept jobs that it does not have enough space for.  In
 such a situation, a Printer object MAY stop reading data from a
 client for an indefinite period of time.  A client MUST be prepared
 for a write operation to block for an indefinite period of time (see
 section 5.1 on client conformance).
 When a Printer object has too little space for starting a new job, it
 MAY reject a new create request. In this case, a Printer object MUST
 return a response (in reply to the rejected request) with a status-
 code of 'server-error-busy' (see section 14.1.5.8) and it MAY close
 the connection before receiving all bytes of the operation.  A
 Printer SHOULD indicate that it is temporarily unable to accept jobs
 by setting the 'spool-space-full' value in its "printer-state-
 reasons" attribute and removing the value when it can accept another
 job (see section 4.4.12).
 When receiving a 'server-error-busy' status-code in an operation
 response, a client MUST be prepared for the Printer object to close
 the connection before the client has sent all of the data (especially
 for the Print-Job operation). A client MUST be prepared to keep
 submitting a create request until the IPP Printer object accepts the
 create request.
 At job processing time, since the Printer object has already
 responded with a successful status code in the response to the create
 request, if the Printer object detects an error, the Printer object
 is unable to inform the end user of the error with an operation
 status code.   In this case, the Printer, depending on the error, can
 set the job object's "job-state", "job-state-reasons", or "job-
 state-message" attributes to the appropriate value(s) so that later
 queries can report the correct job status.
 Note: Asynchronous notification of events is outside the scope of
 this IPP/1.1 document.

Hastings, et al. Standards Track [Page 40] RFC 2911 IPP/1.1: Model and Semantics September 2000

3.2 Printer Operations

 All Printer operations are directed at Printer objects.  A client
 MUST always supply the "printer-uri" operation attribute in order to
 identify the correct target of the operation.

3.2.1 Print-Job Operation

 This REQUIRED operation allows a client to submit a print job with
 only one document and supply the document data (rather than just a
 reference to the data).  See Section 15 for the suggested steps for
 processing create operations and their Operation and Job Template
 attributes.

3.2.1.1 Print-Job Request

 The following groups of attributes are supplied as part of the
 Print-Job Request:
 Group 1: Operation Attributes
    Natural Language and Character Set:
       The "attributes-charset" and "attributes-natural-language"
       attributes as described in section 3.1.4.1.  The Printer object
       MUST copy these values to the corresponding Job Description
       attributes described in sections 4.3.19 and 4.3.20.
    Target:
       The "printer-uri" (uri) operation attribute which is the target
       for this operation as described in section 3.1.5.
    Requesting User Name:
       The "requesting-user-name" (name(MAX)) attribute SHOULD be
       supplied by the client as described in section 8.3.
    "job-name" (name(MAX)):
       The client OPTIONALLY supplies this attribute.  The Printer
       object MUST support this attribute.  It contains the client
       supplied Job name.  If this attribute is supplied by the
       client, its value is used for the "job-name" attribute of the
       newly created Job object.  The client MAY automatically include
       any information that will help the end-user distinguish amongst
       his/her jobs, such as the name of the application program along
       with information from the document, such as the document name,
       document subject, or source file name.  If this attribute is
       not supplied by the client, the Printer generates a name to use
       in the "job-name" attribute of the newly created Job object
       (see Section 4.3.5).

Hastings, et al. Standards Track [Page 41] RFC 2911 IPP/1.1: Model and Semantics September 2000

    "ipp-attribute-fidelity" (boolean):
       The client OPTIONALLY supplies this attribute.  The Printer
       object MUST support this attribute.  The value 'true' indicates
       that total fidelity to client supplied Job Template attributes
       and values is required, else the Printer object MUST reject the
       Print-Job request.  The value 'false' indicates that a
       reasonable attempt to print the Job object is acceptable and
       the Printer object MUST accept the Print-Job request. If not
       supplied, the Printer object assumes the value is 'false'.  All
       Printer objects MUST support both types of job processing.  See
       section 15 for a full description of "ipp-attribute-fidelity"
       and its relationship to other attributes, especially the
       Printer object's "pdl-override-supported" attribute.
    "document-name" (name(MAX)):
       The client OPTIONALLY supplies this attribute.  The Printer
       object MUST support this attribute.   It contains the client
       supplied document name.  The document name MAY be different
       than the Job name.  Typically, the client software
       automatically supplies the document name on behalf of the end
       user by using a file name or an application generated name.  If
       this attribute is supplied, its value can be used in a manner
       defined by each implementation.  Examples include: printed
       along with the Job (job start sheet, page adornments, etc.),
       used by accounting or resource tracking management tools, or
       even stored along with the document as a document level
       attribute.  IPP/1.1 does not support the concept of document
       level attributes.
    "compression" (type3 keyword):
       The client OPTIONALLY supplies this attribute.  The Printer
       object MUST support this attribute and the "compression-
       supported" attribute (see section 4.4.32).  The client supplied
       "compression" operation attribute identifies the compression
       algorithm used on the document data. The following cases exist:
       a) If the client omits this attribute, the Printer object MUST
          assume that the data is not compressed   (i.e. the Printer
          follows the rules below as if the client supplied the
          "compression" attribute with a value of 'none').
       b) If the client supplies this attribute, but the value is not
          supported by the Printer object, i.e., the value is not one
          of the values of the Printer object's "compression-
          supported" attribute, the Printer object MUST reject the
          request, and return the 'client-error-compression-not-
          supported' status code. See section 3.1.7 for returning
          unsupported attributes and values.

Hastings, et al. Standards Track [Page 42] RFC 2911 IPP/1.1: Model and Semantics September 2000

       c) If the client supplies the attribute and the Printer object
          supports the attribute value, the Printer object uses the
          corresponding decompression algorithm on the document data.
       d) If the decompression algorithm fails before the Printer
          returns an operation response, the Printer object MUST
          reject the request and return the 'client-error-
          compression-error' status code.
       e) If the decompression algorithm fails after the Printer
          returns an operation response, the Printer object MUST abort
          the job and add the 'compression-error' value to the job's
          "job-state-reasons" attribute.
       f) If the decompression algorithm succeeds, the document data
          MUST then have the format specified by the job's "document-
          format" attribute, if supplied (see "document-format"
          operation attribute definition below).
    "document-format" (mimeMediaType):
       The client OPTIONALLY supplies this attribute.  The Printer
       object MUST support this attribute.  The value of this
       attribute identifies the format of the supplied document data.
       The following cases exist:
       a) If the client does not supply this attribute, the Printer
          object assumes that the document data is in the format
          defined by the Printer object's "document-format-default"
          attribute. (i.e. the Printer follows the rules below as if
          the client supplied the "document-format" attribute with a
          value equal to the printer's default value).
       b) If the client supplies this attribute, but the value is not
          supported by the Printer object, i.e., the value is not one
          of the values of the Printer object's "document-format-
          supported" attribute, the Printer object MUST reject the
          request and return the 'client-error-document-format-not-
          supported' status code.
       c) If the client supplies this attribute and its value is
          'application/octet-stream' (i.e. to be auto-sensed, see
          Section 4.1.9.1), and the format is not one of the
          document-formats that the Printer can auto-sense, and this
          check occurs before the Printer returns an operation
          response, then the Printer MUST reject the request and
          return the  'client-error-document-format-not-supported'
          status code.
       d) If the client supplies this attribute, and the value is
          supported by the Printer object, the Printer is capable of
          interpreting the document data.

Hastings, et al. Standards Track [Page 43] RFC 2911 IPP/1.1: Model and Semantics September 2000

       e) If interpreting of the document data fails before the
          Printer returns an operation response, the Printer object
          MUST reject the request and return the 'client-error-
          document-format-error' status code.
       f) If interpreting of the document data fails after the Printer
          returns an operation response, the Printer object MUST abort
          the job and add the 'document-format-error' value to the
          job's "job-state-reasons" attribute.
    "document-natural-language" (naturalLanguage):
       The client OPTIONALLY supplies this attribute.  The Printer
       object OPTIONALLY supports this attribute. This attribute
       specifies the natural language of the document for those
       document-formats that require a specification of the natural
       language in order to image the document unambiguously. There
       are no particular values required for the Printer object to
       support.
    "job-k-octets" (integer(0:MAX)):
       The client OPTIONALLY supplies this attribute.  The Printer
       object OPTIONALLY supports this attribute and the "job-k-
       octets-supported" attribute (see section 4.4.33).  The client
       supplied "job-k-octets" operation attribute identifies the
       total size of the document(s) in K octets being submitted (see
       section 4.3.17.1 for the complete semantics).  If the client
       supplies the attribute and the Printer object supports the
       attribute, the value of the attribute is used to populate the
       Job object's "job-k-octets" Job Description attribute.
       For this attribute and the following two attributes ("job-
       impressions", and "job-media-sheets"), if the client supplies
       the attribute, but the Printer object does not support the
       attribute, the Printer object ignores the client-supplied
       value.  If the client supplies the attribute and the Printer
       supports the attribute, and the value is within the range of
       the corresponding Printer object's "xxx-supported" attribute,
       the Printer object MUST use the value to populate the Job
       object's "xxx" attribute.  If the client supplies the attribute
       and the Printer supports the attribute, but the value is
       outside the range of the corresponding Printer object's "xxx-
       supported" attribute, the Printer object MUST copy the
       attribute and its value to the Unsupported Attributes response
       group, reject the request, and return the 'client-error-
       attributes-or-values-not-supported' status code.  If the client
       does not supply the attribute, the Printer object MAY choose to
       populate the corresponding Job object attribute depending on
       whether the Printer object supports the attribute and is able
       to calculate or discern the correct value.

Hastings, et al. Standards Track [Page 44] RFC 2911 IPP/1.1: Model and Semantics September 2000

    "job-impressions" (integer(0:MAX)):
       The client OPTIONALLY supplies this attribute.  The Printer
       object OPTIONALLY supports this attribute and the "job-
       impressions-supported" attribute (see section 4.4.34).  The
       client supplied "job-impressions" operation attribute
       identifies the total size in number of impressions of the
       document(s) being submitted (see section 4.3.17.2 for the
       complete semantics).
       See last paragraph under "job-k-octets".
    "job-media-sheets" (integer(0:MAX)):
       The client OPTIONALLY supplies this attribute.  The Printer
       object OPTIONALLY supports this attribute and the "job-media-
       sheets-supported" attribute (see section 4.4.35).  The client
       supplied "job-media-sheets" operation attribute identifies the
       total number of media sheets to be produced for this job (see
       section 4.3.17.3 for the complete semantics).
       See last paragraph under "job-k-octets".
 Group 2: Job Template Attributes
    The client OPTIONALLY supplies a set of Job Template attributes as
    defined in section 4.2.  If the client is not supplying any Job
    Template attributes in the request, the client SHOULD omit Group 2
    rather than sending an empty group.  However, a Printer object
    MUST be able to accept an empty group.
 Group 3: Document Content
    The client MUST supply the document data to be processed.
    In addition to the MANDATORY parameters required for every
    operation request, the simplest Print-Job Request consists of just
    the "attributes-charset" and "attributes-natural-language"
    operation attributes; the "printer-uri" target operation
    attribute; the Document Content and nothing else.  In this simple
    case, the Printer object:
  1. creates a new Job object (the Job object contains a single

document),

  1. stores a generated Job name in the "job-name" attribute in the

natural language and charset requested (see Section 3.1.4.1) (if

      those are supported, otherwise using the Printer object's
      default natural language and charset), and

Hastings, et al. Standards Track [Page 45] RFC 2911 IPP/1.1: Model and Semantics September 2000

  1. at job processing time, uses its corresponding default value

attributes for the supported Job Template attributes that were

      not supplied by the client as IPP attribute or embedded
      instructions in the document data.

3.2.1.2 Print-Job Response

 The Printer object MUST return to the client the following sets of
 attributes as part of the Print-Job Response:
 Group 1: Operation Attributes
    Status Message:
       In addition to the REQUIRED status code returned in every
       response, the response OPTIONALLY includes a "status-message"
       (text(255)) and/or a "detailed-status-message" (text(MAX))
       operation attribute as described in sections 13 and 3.1.6.  If
       the client supplies unsupported or conflicting Job Template
       attributes or values, the Printer object MUST reject or accept
       the Print-Job request depending on the whether the client
       supplied a 'true' or 'false' value for the "ipp-attribute-
       fidelity" operation attribute.  See the Implementer's Guide
       [IPP-IIG] for a complete description of the suggested steps for
       processing a create request.
    Natural Language and Character Set:
       The "attributes-charset" and "attributes-natural-language"
       attributes as described in section 3.1.4.2.
 Group 2: Unsupported Attributes
    See section 3.1.7 for details on returning Unsupported Attributes.
    The value of the "ipp-attribute-fidelity" supplied by the client
    does not affect what attributes the Printer object returns in this
    group.  The value of "ipp-attribute-fidelity" only affects whether
    the Print-Job operation is accepted or rejected.  If the job is
    accepted, the client may query the job using the Get-Job-
    Attributes operation requesting the unsupported attributes that
    were returned in the create response to see which attributes were
    ignored (not stored on the Job object) and which attributes were
    stored with other (substituted) values.

Hastings, et al. Standards Track [Page 46] RFC 2911 IPP/1.1: Model and Semantics September 2000

 Group 3: Job Object Attributes
    "job-uri" (uri):
       The Printer object MUST return the Job object's URI by
       returning the contents of the REQUIRED "job-uri" Job object
       attribute.  The client uses the Job object's URI when directing
       operations at the Job object.  The Printer object always uses
       its configured security policy when creating the new URI.
       However, if the Printer object supports more than one URI, the
       Printer object also uses information about which URI was used
       in the Print-Job Request to generated the new URI so that the
       new URI references the correct access channel.  In other words,
       if the Print-Job Request comes in over a secure channel, the
       Printer object MUST generate a Job URI that uses the secure
       channel as well.
    "job-id" (integer(1:MAX)):
       The Printer object MUST return the Job object's Job ID by
       returning the REQUIRED  "job-id" Job object attribute.  The
       client uses this "job-id" attribute in conjunction with the
       "printer-uri" attribute used in the Print-Job Request when
       directing Job operations at the Printer object.
    "job-state" (type1 enum):
       The Printer object MUST return the Job object's REQUIRED "job-
       state" attribute. The value of this attribute (along with the
       value of the next attribute:  "job-state-reasons") is taken
       from a "snapshot" of the new Job object at some meaningful
       point in time (implementation defined) between when the Printer
       object receives the Print-Job Request and when the Printer
       object returns the response.
    "job-state-reasons" (1setOf type2 keyword):
       The Printer object MUST return the Job object's REQUIRED "job-
       state-reasons" attribute.
    "job-state-message" (text(MAX)):
       The Printer object OPTIONALLY returns the Job object's OPTIONAL
       "job-state-message" attribute.  If the Printer object supports
       this attribute then it MUST be returned in the response.  If
       this attribute is not returned in the response, the client can
       assume that the "job-state-message" attribute is not supported
       and will not be returned in a subsequent Job object query.
    "number-of-intervening-jobs" (integer(0:MAX)):
       The Printer object OPTIONALLY returns the Job object's OPTIONAL
       "number-of-intervening-jobs" attribute.  If the Printer object
       supports this attribute then it MUST be returned in the

Hastings, et al. Standards Track [Page 47] RFC 2911 IPP/1.1: Model and Semantics September 2000

       response.  If this attribute is not returned in the response,
       the client can assume that the "number-of-intervening-jobs"
       attribute is not supported and will not be returned in a
       subsequent Job object query.
       Note: Since any printer state information which affects a job's
       state is reflected in the "job-state" and "job-state-reasons"
       attributes, it is sufficient to return only these attributes
       and no specific printer status attributes.
 Note: In addition to the MANDATORY parameters required for every
 operation response, the simplest response consists of the just the
 "attributes-charset" and "attributes-natural-language" operation
 attributes and the "job-uri", "job-id", and "job-state" Job Object
 Attributes.  In this simplest case, the status code is 'successful-
 ok' and there is no "status-message" or "detailed-status-message"
 operation attribute.

3.2.2 Print-URI Operation

 This OPTIONAL operation is identical to the Print-Job operation
 (section 3.2.1) except that a client supplies a URI reference to the
 document data using the "document-uri" (uri) operation attribute (in
 Group 1) rather than including the document data itself.  Before
 returning the response, the Printer MUST validate that the Printer
 supports the retrieval method (e.g., http, ftp, etc.) implied by the
 URI, and MUST check for valid URI syntax.  If the client-supplied URI
 scheme is not supported, i.e. the value is not in the Printer
 object's "referenced-uri-scheme-supported" attribute, the Printer
 object MUST reject the request and return the 'client-error-uri-
 scheme-not-supported' status code.
 The IPP Printer MAY validate the accessibility of the document as
 part of the operation or subsequently.  If the Printer determines an
 accessibility problem before returning an operation response, it
 rejects the request and returns the 'client-error-document-access-
 error' status code.  The Printer MAY also return a specific document
 access error code using the "document-access-error" operation
 attribute (see section 3.1.6.4).
 If the Printer determines this document accessibility problem after
 accepting the request and returning an operation response with one of
 the successful status codes, the Printer adds the 'document-access-
 error' value to the job's "job-state-reasons" attribute and MAY
 populate the job's "job-document-access-errors" Job Description
 attribute (see section 4.3.11).  See The Implementer's Guide [IPP-
 IIG] for suggested additional checks.

Hastings, et al. Standards Track [Page 48] RFC 2911 IPP/1.1: Model and Semantics September 2000

 If the Printer object supports this operation, it MUST support the
 "reference-uri-schemes-supported" Printer attribute (see section
 4.4.27).
 It is up to the IPP object to interpret the URI and subsequently
 "pull" the document from the source referenced by the URI string.

3.2.3 Validate-Job Operation

 This REQUIRED operation is similar to the Print-Job operation
 (section 3.2.1) except that a client supplies no document data and
 the Printer allocates no resources (i.e., it does not create a new
 Job object).  This operation is used only to verify capabilities of a
 printer object against whatever attributes are supplied by the client
 in the Validate-Job request.  By using the Validate-Job operation a
 client can validate that an identical Print-Job operation (with the
 document data) would be accepted. The Validate-Job operation also
 performs the same security negotiation as the Print-Job operation
 (see section 8), so that a client can check that the client and
 Printer object security requirements can be met before performing a
 Print-Job operation.
 The Validate-Job operation does not accept a "document-uri" attribute
 in order to allow a client to check that the same Print-URI operation
 will be accepted, since the client doesn't send the data with the
 Print-URI operation.  The client SHOULD just issue the Print-URI
 request.
 The Printer object returns the same status codes, Operation
 Attributes (Group 1) and Unsupported Attributes (Group 2) as the
 Print-Job operation.  However, no Job Object Attributes (Group 3) are
 returned, since no Job object is created.

3.2.4 Create-Job Operation

 This OPTIONAL operation is similar to the Print-Job operation
 (section 3.2.1) except that in the Create-Job request, a client does
 not supply document data or any reference to document data.  Also,
 the client does not supply any of the "document-name", "document-
 format", "compression", or "document-natural-language" operation
 attributes.  This operation is followed by one or more Send-Document
 or Send-URI operations.  In each of those operation requests, the
 client OPTIONALLY supplies the "document-name", "document-format",
 and "document-natural-language" attributes for each document in the
 multi-document Job object.

Hastings, et al. Standards Track [Page 49] RFC 2911 IPP/1.1: Model and Semantics September 2000

 If a Printer object supports the Create-Job operation, it MUST also
 support the Send-Document operation and also MAY support the Send-URI
 operation.
 If the Printer object supports this operation, it MUST support the
 "multiple-operation-time-out" Printer attribute (see section 4.4.31).
 If the Printer object supports this operation, then it MUST support
 the "multiple-document-jobs-supported" Printer Description attribute
 (see section 4.4.16) and indicate whether or not it supports
 multiple-document jobs.
 If the Printer object supports this operation and supports multiple
 documents in a job, then it MUST support the "multiple-document-
 handling" Job Template job attribute with at least one value (see
 section 4.2.4) and the associated "multiple-document-handling-
 default" and "multiple-document-handling-supported" Job Template
 Printer attributes (see section 4.2).
 After the Create-Job operation has completed, the value of the "job-
 state" attribute is similar to the "job-state" after a Print-Job,
 even though no document-data has arrived.  A Printer MAY set the
 'job-data-insufficient' value of the job's "job-state-reason"
 attribute to indicate that processing cannot begin until sufficient
 data has arrived and set the "job-state" to either 'pending' or
 'pending-held'.  A non-spooling printer that doesn't implement the
 'pending' job state may even set the "job-state" to 'processing',
 even though there is not yet any data to process.  See sections 4.3.7
 and 4.3.8.

3.2.5 Get-Printer-Attributes Operation

 This REQUIRED operation allows a client to request the values of the
 attributes of a Printer object.   In the request, the client supplies
 the set of Printer attribute names and/or attribute group names in
 which the requester is interested.  In the response, the Printer
 object returns a corresponding attribute set with the appropriate
 attribute values filled in.
 For Printer objects, the possible names of attribute groups are:
  1. 'job-template': the subset of the Job Template attributes that

apply to a Printer object (the last two columns of the table in

      Section 4.2) that the implementation supports for Printer
      objects.
    - 'printer-description': the subset of the attributes specified in
      Section 4.4 that the implementation supports for Printer
      objects.

Hastings, et al. Standards Track [Page 50] RFC 2911 IPP/1.1: Model and Semantics September 2000

  1. 'all': the special group 'all' that includes all attributes that

the implementation supports for Printer objects.

 Since a client MAY request specific attributes or named groups, there
 is a potential that there is some overlap.  For example, if a client
 requests, 'printer-name' and 'all', the client is actually requesting
 the "printer-name" attribute twice: once by naming it explicitly, and
 once by inclusion in the 'all' group.  In such cases, the Printer
 object NEED NOT return each attribute only once in the response even
 if it is requested multiple times.  The client SHOULD NOT request the
 same attribute in multiple ways.
 It is NOT REQUIRED that a Printer object support all attributes
 belonging to a group (since some attributes are OPTIONAL).  However,
 it is REQUIRED that each Printer object support all group names.

3.2.5.1 Get-Printer-Attributes Request

 The following sets of attributes are part of the Get-Printer-
 Attributes Request:
 Group 1: Operation Attributes
    Natural Language and Character Set:
       The "attributes-charset" and "attributes-natural-language"
       attributes as described in section 3.1.4.1.
    Target:
       The "printer-uri" (uri) operation attribute which is the target
       for this operation as described in section 3.1.5.
    Requesting User Name:
       The "requesting-user-name" (name(MAX)) attribute SHOULD be
       supplied by the client as described in section 8.3.
    "requested-attributes" (1setOf keyword):
       The client OPTIONALLY supplies a set of attribute names and/or
       attribute group names in whose values the requester is
       interested.  The Printer object MUST support this attribute.
       If the client omits this attribute, the Printer MUST respond as
       if this attribute had been supplied with a value of 'all'.
    "document-format" (mimeMediaType):
       The client OPTIONALLY supplies this attribute.  The Printer
       object MUST support this attribute.  This attribute is useful
       for a Printer object to determine the set of supported
       attribute values that relate to the requested document format.
       The Printer object MUST return the attributes and values that

Hastings, et al. Standards Track [Page 51] RFC 2911 IPP/1.1: Model and Semantics September 2000

       it uses to validate a job on a create or Validate-Job operation
       in which this document format is supplied. The Printer object
       SHOULD return only (1) those attributes that are supported for
       the specified format and (2) the attribute values that are
       supported for the specified document format.  By specifying the
       document format, the client can get the Printer object to
       eliminate the attributes and values that are not supported for
       a specific document format.  For example, a Printer object
       might have multiple interpreters to support both
       'application/postscript' (for PostScript) and 'text/plain' (for
       text) documents.  However, for only one of those interpreters
       might the Printer object be able to support "number-up" with
       values of '1', '2', and '4'.  For the other interpreter it
       might be able to only support "number-up" with a value of '1'.
       Thus a client can use the Get-Printer-Attributes operation to
       obtain the attributes and values that will be used to
       accept/reject a create job operation.
       If the Printer object does not distinguish between different
       sets of supported values for each different document format
       when validating jobs in the create and Validate-Job operations,
       it MUST NOT distinguish between different document formats in
       the Get-Printer-Attributes operation. If the Printer object
       does distinguish between different sets of supported values for
       each different document format specified by the client, this
       specialization applies only to the following Printer object
       attributes:
  1. Printer attributes that are Job Template attributes ("xxx-

default" "xxx-supported", and "xxx-ready" in the Table in

      Section 4.2),
    - "pdl-override-supported",
    - "compression-supported",
    - "job-k-octets-supported",
    - "job-impressions-supported",
    - "job-media-sheets-supported",
    - "printer-driver-installer",
    - "color-supported", and
    - "reference-uri-schemes-supported"
    The values of all other Printer object attributes (including
    "document-format-supported") remain invariant with respect to the
    client supplied document format (except for new Printer
    description attribute as registered according to section 6.2).
    If the client omits this "document-format" operation attribute,
    the Printer object MUST respond as if the attribute had been
    supplied with the value of the Printer object's "document-format-

Hastings, et al. Standards Track [Page 52] RFC 2911 IPP/1.1: Model and Semantics September 2000

    default" attribute.  It is RECOMMENDED that the client always
    supply a value for "document-format", since the Printer object's
    "document-format-default" may be 'application/octet-stream', in
    which case the returned attributes and values are for the union of
    the document formats that the Printer can automatically sense.
    For more details, see the description of the 'mimeMediaType'
    attribute syntax in section 4.1.9.
    If the client supplies a value for the "document-format" Operation
    attribute that is not supported by the Printer, i.e., is not among
    the values of the Printer object's "document-format-supported"
    attribute, the Printer object MUST reject the operation and return
    the 'client-error-document-format-not-supported' status code.

3.2.5.2 Get-Printer-Attributes Response

 The Printer object returns the following sets of attributes as part
 of the Get-Printer-Attributes Response:
 Group 1: Operation Attributes
    Status Message:
      In addition to the REQUIRED status code returned in every
      response, the response OPTIONALLY includes a "status-message"
      (text(255)) and/or a "detailed-status-message" (text(MAX))
      operation attribute as described in sections 13 and  3.1.6.
    Natural Language and Character Set:
      The "attributes-charset" and "attributes-natural-language"
      attributes as described in section 3.1.4.2.
 Group 2: Unsupported Attributes
    See section 3.1.7 for details on returning Unsupported Attributes.
    The response NEED NOT contain the "requested-attributes" operation
    attribute with any supplied values (attribute keywords) that were
    requested by the client but are not supported by the IPP object.
    If the Printer object does return unsupported attributes
    referenced in the "requested-attributes" operation attribute and
    that attribute included group names, such as 'all', the
    unsupported attributes MUST NOT include attributes described in
    the standard but not supported by the implementation.

Hastings, et al. Standards Track [Page 53] RFC 2911 IPP/1.1: Model and Semantics September 2000

 Group 3: Printer Object Attributes
    This is the set of requested attributes and their current values.
    The Printer object ignores (does not respond with) any requested
    attribute which is not supported.  The Printer object MAY respond
    with a subset of the supported attributes and values, depending on
    the security policy in force.  However, the Printer object MUST
    respond with the 'unknown' value for any supported attribute
    (including all REQUIRED attributes) for which the Printer object
    does not know the value.  Also the Printer object MUST respond
    with the 'no-value' for any supported attribute (including all
    REQUIRED attributes) for which the system administrator has not
    configured a value.  See the description of the "out-of-band"
    values in the beginning of Section 4.1.

3.2.6 Get-Jobs Operation

 This REQUIRED operation allows a client to retrieve the list of Job
 objects belonging to the target Printer object.  The client may also
 supply a list of Job attribute names and/or attribute group names.  A
 group of Job object attributes will be returned for each Job object
 that is returned.
 This operation is similar to the Get-Job-Attributes operation, except
 that this Get-Jobs operation returns attributes from possibly more
 than one object.

3.2.6.1 Get-Jobs Request

 The client submits the Get-Jobs request to a Printer object.
 The following groups of attributes are part of the Get-Jobs Request:
 Group 1: Operation Attributes
    Natural Language and Character Set:
       The "attributes-charset" and "attributes-natural-language"
       attributes as described in section 3.1.4.1.
    Target:
       The "printer-uri" (uri) operation attribute which is the target
       for this operation as described in section 3.1.5.
    Requesting User Name:
       The "requesting-user-name" (name(MAX)) attribute SHOULD be
       supplied by the client as described in section 8.3.

Hastings, et al. Standards Track [Page 54] RFC 2911 IPP/1.1: Model and Semantics September 2000

    "limit" (integer(1:MAX)):
       The client OPTIONALLY supplies this attribute.  The Printer
       object MUST support this attribute. It is an integer value that
       determines the maximum number of jobs that a client will
       receive from the Printer even if "which-jobs" or "my-jobs"
       constrain which jobs are returned.  The limit is a "stateless
       limit" in that if the value supplied by the client is 'N', then
       only the first 'N' jobs are returned in the Get-Jobs Response.
       There is no mechanism to allow for the next 'M' jobs after the
       first 'N' jobs.  If the client does not supply this attribute,
       the Printer object responds with all applicable jobs.
    "requested-attributes" (1setOf type2 keyword):
       The client OPTIONALLY supplies this attribute.  The Printer
       object MUST support this attribute.  It is a set of Job
       attribute names and/or attribute groups names in whose values
       the requester is interested.  This set of attributes is
       returned for each Job object that is returned.  The allowed
       attribute group names are the same as those defined in the
       Get-Job-Attributes operation in section 3.3.4.  If the client
       does not supply this attribute, the Printer MUST respond as if
       the client had supplied this attribute with two values: 'job-
       uri' and 'job-id'.
    "which-jobs" (type2 keyword):
       The client OPTIONALLY supplies this attribute.  The Printer
       object MUST support this attribute.  It indicates which Job
       objects MUST be returned by the Printer object. The values for
       this attribute are:
    'completed': This includes any Job object whose state is
       'completed', 'canceled', or 'aborted'.
    'not-completed': This includes any Job object whose state is
       'pending', 'processing', 'processing-stopped', or 'pending-
       held'.
       A Printer object MUST support both values.  However, if the
       implementation does not keep jobs in the 'completed',
       'canceled', and 'aborted' states, then it returns no jobs when
       the 'completed' value is supplied.
       If a client supplies some other value, the Printer object MUST
       copy the attribute and the unsupported value to the Unsupported
       Attributes response group, reject the request, and return the
       'client-error-attributes-or-values-not-supported' status code.

Hastings, et al. Standards Track [Page 55] RFC 2911 IPP/1.1: Model and Semantics September 2000

       If the client does not supply this attribute, the Printer
       object MUST respond as if the client had supplied the attribute
       with a value of 'not-completed'.
    "my-jobs" (boolean):
       The client OPTIONALLY supplies this attribute.  The Printer
       object MUST support this attribute.  It indicates whether jobs
       from all users or just the jobs submitted by the requesting
       user of this request MUST be considered as candidate jobs to be
       returned by the Printer object.  If the client does not supply
       this attribute, the Printer object MUST respond as if the
       client had supplied the attribute with a value of 'false',
       i.e., jobs from all users.  The means for authenticating the
       requesting user and matching the jobs is described in section
       8.

3.2.6.2 Get-Jobs Response

 The Printer object returns all of the Job objects up to the number
 specified by the "limit" attribute that match the criteria as defined
 by the attribute values supplied by the client in the request.  It is
 possible that no Job objects are returned since there may literally
 be no Job objects at the Printer, or there may be no Job objects that
 match the criteria supplied by the client.  If the client requests
 any Job attributes at all, there is a set of Job Object Attributes
 returned for each Job object.
 It is not an error for the Printer to return 0 jobs. If the response
 returns 0 jobs because there are no jobs matching the criteria, and
 the request would have returned 1 or more jobs with a status code of
 'successful-ok' if there had been jobs matching the criteria, then
 the status code for 0 jobs MUST be 'successful-ok'.
 Group 1: Operation Attributes
    Status Message:
      In addition to the REQUIRED status code returned in every
      response, the response OPTIONALLY includes a "status-message"
      (text(255)) and/or a "detailed-status-message" (text(MAX))
      operation attribute as described in sections 13 and 3.1.6.
    Natural Language and Character Set:
      The "attributes-charset" and "attributes-natural-language"
      attributes as described in section 3.1.4.2.

Hastings, et al. Standards Track [Page 56] RFC 2911 IPP/1.1: Model and Semantics September 2000

 Group 2: Unsupported Attributes
    See section 3.1.7 for details on returning Unsupported Attributes.
    The response NEED NOT contain the "requested-attributes" operation
    attribute with any supplied values (attribute keywords) that were
    requested by the client but are not supported by the IPP object.
    If the Printer object does return unsupported attributes
    referenced in the "requested-attributes" operation attribute and
    that attribute included group names, such as 'all', the
    unsupported attributes MUST NOT include attributes described in
    the standard but not supported by the implementation.
 Groups 3 to N: Job Object Attributes
    The Printer object responds with one set of Job Object Attributes
    for each returned Job object.  The Printer object ignores (does
    not respond with) any requested attribute or value which is not
    supported or which is restricted by the security policy in force,
    including whether the requesting user is the user that submitted
    the job (job originating user) or not (see section 8).  However,
    the Printer object MUST respond with the 'unknown' value for any
    supported attribute (including all REQUIRED attributes) for which
    the Printer object does not know the value, unless it would
    violate the security policy.  See the description of the "out-of-
    band" values in the beginning of Section 4.1.
    Jobs are returned in the following order:
  1. If the client requests all 'completed' Jobs (Jobs in the

'completed', 'aborted', or 'canceled' states), then the Jobs are

      returned newest to oldest (with respect to actual completion
      time)
    - If the client requests all 'not-completed' Jobs (Jobs in the
      'pending', 'processing', 'pending-held', and 'processing-
      stopped' states), then Jobs are returned in relative
      chronological order of expected time to complete (based on
      whatever scheduling algorithm is configured for the Printer
      object).

3.2.7 Pause-Printer Operation

 This OPTIONAL operation allows a client to stop the Printer object
 from scheduling jobs on all its devices.  Depending on
 implementation, the Pause-Printer operation MAY also stop the Printer
 from processing the current job or jobs.  Any job that is currently
 being printed is either stopped as soon as the implementation permits

Hastings, et al. Standards Track [Page 57] RFC 2911 IPP/1.1: Model and Semantics September 2000

 or is completed, depending on implementation.  The Printer object
 MUST still accept create operations to create new jobs, but MUST
 prevent any jobs from entering the 'processing' state.
 If the Pause-Printer operation is supported, then the Resume-Printer
 operation MUST be supported, and vice-versa.
 The IPP Printer stops the current job(s) on its device(s) that were
 in the 'processing' or 'processing-stopped' states as soon as the
 implementation permits.  If the implementation will take appreciable
 time to stop, the IPP Printer adds the 'moving-to-paused' value to
 the Printer object's "printer-state-reasons" attribute (see section
 4.4.12).  When the device(s) have all stopped, the IPP Printer
 transitions the Printer object to the 'stopped' state, removes the
 'moving-to-paused' value, if present, and adds the 'paused' value to
 the Printer object's "printer-state-reasons" attribute.
 When the current job(s) complete that were in the 'processing' state,
 the IPP Printer transitions them to the 'completed' state.  When the
 current job(s) stop in mid processing that were in the 'processing'
 state, the IPP Printer transitions them to the 'processing-stopped'
 state and adds the 'printer-stopped' value to the job's "job-state-
 reasons" attribute.
 For any jobs that are 'pending' or 'pending-held', the 'printer-
 stopped' value of the jobs' "job-state-reasons" attribute also
 applies.  However, the IPP Printer NEED NOT update those jobs' "job-
 state-reasons" attributes and only need return the 'printer-stopped'
 value when those jobs are queried (so-called "lazy evaluation").
 Whether the Pause-Printer operation affects jobs that were submitted
 to the device from other sources than the IPP Printer object in the
 same way that the Pause-Printer operation affects jobs that were
 submitted to the IPP Printer object using IPP, depends on
 implementation, i.e., on whether the IPP protocol is being used as a
 universal management protocol or just to manage IPP jobs,
 respectively.
 The IPP Printer MUST accept the request in any state and transition
 the Printer to the indicated new "printer-state" before returning as
 follows:

Hastings, et al. Standards Track [Page 58] RFC 2911 IPP/1.1: Model and Semantics September 2000

   Current        New      "printer   IPP Printer's response status
  "printer-    "printer-   -state-          code and action:
   state"       state"    reasons"
'idle'       'stopped'    'paused'  'successful-ok'
'processing' 'processing' 'moving-  OPTION 1: 'successful-ok';
                            to-       Later, when all output has
                            paused'   stopped, the "printer-state"
                                      becomes 'stopped', and the
                                      'paused' value replaces the
                                      'moving-to-paused' value in the
                                      "printer-state-reasons"
                                      attribute
'processing' 'stopped'    'paused'  OPTION 2: 'successful-ok';
                                      all device output stopped
                                      immediately
'stopped'    'stopped'    'paused'  'successful-ok'
 Access Rights: The authenticated user (see section 8.3) performing
 this operation must be an operator or administrator of the Printer
 object (see Sections 1 and 8.5).   Otherwise, the IPP Printer MUST
 reject the operation and return:  'client-error-forbidden', 'client-
 error-not-authenticated', or 'client-error-not-authorized' as
 appropriate.

3.2.7.1 Pause-Printer Request

 The following groups of attributes are part of the Pause-Printer
 Request:
 Group 1: Operation Attributes
    Natural Language and Character Set:
      The "attributes-charset" and "attributes-natural-language"
      attributes as described in section 3.1.4.1.
    Target:
      The "printer-uri" (uri) operation attribute which is the target
      for this operation as described in section 3.1.5.
    Requesting User Name:
      The "requesting-user-name" (name(MAX)) attribute SHOULD be
      supplied by the client as described in section 8.3.

Hastings, et al. Standards Track [Page 59] RFC 2911 IPP/1.1: Model and Semantics September 2000

3.2.7.2 Pause-Printer Response

 The following groups of attributes are part of the Pause-Printer
 Response:
 Group 1: Operation Attributes
    Status Message:
      In addition to the REQUIRED status code returned in every
      response, the response OPTIONALLY includes a "status-message"
      (text(255)) and/or a "detailed-status-message" (text(MAX))
      operation attribute as described in sections 13 and  3.1.6.
    Natural Language and Character Set:
      The "attributes-charset" and "attributes-natural-language"
      attributes as described in section 3.1.4.2.
 Group 2: Unsupported Attributes
    See section 3.1.7 for details on returning Unsupported Attributes.

3.2.8 Resume-Printer Operation

 This operation allows a client to resume the Printer object
 scheduling jobs on all its devices.  The Printer object MUST remove
 the 'paused' and 'moving-to-paused' values from the Printer object's
 "printer-state-reasons" attribute, if present.  If there are no other
 reasons to keep a device paused (such as media-jam), the IPP Printer
 is free to transition itself to the 'processing' or 'idle' states,
 depending on whether there are jobs to be processed or not,
 respectively, and the device(s) resume processing jobs.
 If the Pause-Printer operation is supported, then the Resume-Printer
 operation MUST be supported, and vice-versa.
 The IPP Printer removes the 'printer-stopped' value from any job's
 "job-state-reasons" attributes contained in that Printer.
 The IPP Printer MUST accept the request in any state, transition the
 Printer object to the indicated new state as follows:

Hastings, et al. Standards Track [Page 60] RFC 2911 IPP/1.1: Model and Semantics September 2000

   Current    New "printer-  IPP Printer's response status code and
  "printer-      state"                     action:
    state"
 'idle'       'idle'         'successful-ok'
 'processing' 'processing'   'successful-ok'
 'stopped'    'processing'   'successful-ok';
                             when there are jobs to be processed
 'stopped'    'idle'         'successful-ok';
                             when there are no jobs to be processed.
 Access Rights: The authenticated user (see section 8.3) performing
 this operation must be an operator or administrator of the Printer
 object (see Sections 1 and 8.5).  Otherwise, the IPP Printer MUST
 reject the operation and return:  'client-error-forbidden', 'client-
 error-not-authenticated', or 'client-error-not-authorized' as
 appropriate.
 The Resume-Printer Request and Resume-Printer Response have the same
 attribute groups and attributes as the Pause-Printer operation (see
 sections 3.2.7.1 and 3.2.7.2).

3.2.9 Purge-Jobs Operation

 This OPTIONAL operation allows a client to remove all jobs from an
 IPP Printer object, regardless of their job states, including jobs in
 the Printer object's Job History (see Section 4.3.7.2).  After a
 Purge-Jobs operation has been performed, a Printer object MUST return
 no jobs in subsequent Get-Job-Attributes and Get-Jobs responses
 (until new jobs are submitted).
 Whether the Purge-Jobs (and Get-Jobs) operation affects jobs that
 were submitted to the device from other sources than the IPP Printer
 object in the same way that the Purge-Jobs operation affects jobs
 that were submitted to the IPP Printer object using IPP, depends on
 implementation, i.e., on whether the IPP protocol is being used as a
 universal management protocol or just to manage IPP jobs,
 respectively.
 Note:  if an operator wants to cancel all jobs without clearing out
 the Job History, the operator uses the Cancel-Job operation on each
 job instead of using the Purge-Jobs operation.
 The Printer object MUST accept this operation in any state and
 transition the Printer object to the 'idle' state.

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 Access Rights: The authenticated user (see section 8.3) performing
 this operation must be an operator or administrator of the Printer
 object (see Sections 1 and 8.5).  Otherwise, the IPP object MUST
 reject the operation and return: client-error-forbidden, client-
 error-not-authenticated, and client-error-not-authorized as
 appropriate.
 The Purge-Jobs Request and Purge-Jobs Response have the same
 attribute groups and attributes as the Pause-Printer operation (see
 sections 3.2.7.1 and 3.2.7.2).

3.3 Job Operations

 All Job operations are directed at Job objects.  A client MUST always
 supply some means of identifying the Job object in order to identify
 the correct target of the operation.  That job identification MAY
 either be a single Job URI or a combination of a Printer URI with a
 Job ID.  The IPP object implementation MUST support both forms of
 identification for every job.

3.3.1 Send-Document Operation

 This OPTIONAL operation allows a client to create a multi-document
 Job object that is initially "empty" (contains no documents).  In the
 Create-Job response, the Printer object returns the Job object's URI
 (the "job-uri" attribute) and the Job object's 32-bit identifier (the
 "job-id" attribute).  For each new document that the client desires
 to add, the client uses a Send-Document operation.  Each Send-
 Document Request contains the entire stream of document data for one
 document.
 If the Printer supports this operation but does not support multiple
 documents per job, the Printer MUST reject subsequent Send-Document
 operations supplied with data and return the 'server-error-multiple-
 document-jobs-not-supported'.  However, the Printer MUST accept the
 first document with a 'true' or 'false' value for the "last-document"
 operation attribute (see below), so that clients MAY always submit
 one document jobs with a 'false' value for "last-document" in the
 first Send-Document and a 'true' for "last-document" in the second
 Send-Document (with no data).
 Since the Create-Job and the send operations (Send-Document or Send-
 URI operations) that follow could occur over an arbitrarily long
 period of time for a particular job, a client MUST send another send
 operation within an IPP Printer defined minimum time interval after
 the receipt of the previous request for the job.  If a Printer object
 supports the Create-Job and Send-Document operations, the Printer
 object MUST support the "multiple-operation-time-out" attribute (see

Hastings, et al. Standards Track [Page 62] RFC 2911 IPP/1.1: Model and Semantics September 2000

 section 4.4.31).  This attribute indicates the minimum number of
 seconds the Printer object will wait for the next send operation
 before taking some recovery action.
 An IPP object MUST recover from an errant client that does not supply
 a send operation, sometime after the minimum time interval specified
 by the Printer object's "multiple-operation-time-out" attribute.
 Such recovery MAY include any of the following or other recovery
 actions:
    1. Assume that the Job is an invalid job, start the process of
       changing the job state to 'aborted', add the 'aborted-by-
       system' value to the job's "job-state-reasons" attribute (see
       section 4.3.8), and clean up all resources associated with the
       Job.  In this case, if another send operation is finally
       received, the Printer responds with an "client-error-not-
       possible" or "client-error-not-found" depending on whether or
       not the Job object is still around when the send operation
       finally arrives.
    2. Assume that the last send operation received was in fact the
       last document (as if the "last-document" flag had been set to
       'true'), close the Job object, and proceed to process it (i.e.,
       move the Job's state to 'pending').
    3. Assume that the last send operation received was in fact the
       last document, close the Job, but move it to the 'pending-held'
       and add the 'submission-interrupted' value to the job's "job-
       state-reasons" attribute (see section 4.3.8).  This action
       allows the user or an operator to determine whether to continue
       processing the Job by moving it back to the 'pending' state
       using the Release-Job operation (see section 3.3.6) or to
       cancel the job using the Cancel-Job operation (see section
       3.3.3).
 Each implementation is free to decide the "best" action to take
 depending on local policy, whether any documents have been added,
 whether the implementation spools jobs or not,  and/or any other
 piece of information available to it.  If the choice is to abort the
 Job object, it is possible that the Job object may already have been
 processed to the point that some media sheet pages have been printed.
 Access Rights: The authenticated user (see section 8.3) performing
 this operation must either be the job owner (as determined in the
 Create-Job operation) or an operator or administrator of the Printer
 object (see Sections 1 and 8.5).  Otherwise, the IPP object MUST
 reject the operation and return: 'client-error-forbidden', 'client-
 error-not-authenticated', or 'client-error-not-authorized' as
 appropriate.

Hastings, et al. Standards Track [Page 63] RFC 2911 IPP/1.1: Model and Semantics September 2000

3.3.1.1 Send-Document Request

 The following attribute sets are part of the Send-Document Request:
 Group 1: Operation Attributes
    Natural Language and Character Set:
      The "attributes-charset" and "attributes-natural-language"
      attributes as described in section 3.1.4.1.
    Target:
      Either (1) the "printer-uri" (uri) plus "job-id"
      (integer(1:MAX))or (2) the "job-uri" (uri) operation
      attribute(s) which define the target for this operation as
      described in section 3.1.5.
    Requesting User Name:
      The "requesting-user-name" (name(MAX)) attribute SHOULD be
      supplied by the client as described in section 8.3.
    "document-name" (name(MAX)):
      The client OPTIONALLY supplies this attribute.  The Printer
      object MUST support this attribute.  It contains the client
      supplied document name.  The document name MAY be different than
      the Job name.  It might be helpful, but NEED NOT be unique
      across multiple documents in the same Job.  Typically, the
      client software automatically supplies the document name on
      behalf of the end user by using a file name or an application
      generated name.  See the description of the "document-name"
      operation attribute in the Print-Job Request (section 3.2.1.1)
      for more information about this attribute.
    "compression" (type3 keyword):
      See the description of "compression" for the Print-Job operation
      in Section 3.2.1.1.
    "document-format" (mimeMediaType):
      See the description of "document-format" for the Print-Job
      operation in Section 3.2.1.1.
    "document-natural-language" (naturalLanguage):
      The client OPTIONALLY supplies this attribute.  The Printer
      object OPTIONALLY supports this attribute.  This attribute
      specifies the natural language of the document for those
      document-formats that require a specification of the natural
      language in order to image the document unambiguously.  There
      are no particular values required for the Printer object to
      support.

Hastings, et al. Standards Track [Page 64] RFC 2911 IPP/1.1: Model and Semantics September 2000

    "last-document" (boolean):
      The client MUST supply this attribute.  The Printer object MUST
      support this attribute. It is a boolean flag that is set to
      'true' if this is the last document for the Job, 'false'
      otherwise.
 Group 2: Document Content
    The client MUST supply the document data if the "last-document"
    flag is set to 'false'.  However, since a client might not know
    that the previous document sent with a Send-Document (or Send-URI)
    operation was the last document (i.e., the "last-document"
    attribute was set to 'false'), it is legal to send a Send-Document
    request with no document data where the "last-document" flag is
    set to 'true'.  Such a request MUST NOT increment the value of the
    Job object's "number-of-documents" attribute, since no real
    document was added to the job.  It is not an error for a client to
    submit a job with no actual document data, i.e., only a single
    Create-Job and Send-Document request with a "last-document"
    operation attribute set to 'true' with no document data.

3.3.1.2 Send-Document Response

 The following sets of attributes are part of the Send-Document
 Response:
 Group 1: Operation Attributes
    Status Message:
       In addition to the REQUIRED status code returned in every
       response, the response OPTIONALLY includes a "status-message"
       (text(255)) and/or a "detailed-status-message" (text(MAX))
       operation attribute as described in sections 13 and 3.1.6.
    Natural Language and Character Set:
       The "attributes-charset" and "attributes-natural-language"
       attributes as described in section 3.1.4.2.
 Group 2: Unsupported Attributes
    See section 3.1.7 for details on returning Unsupported Attributes.
 Group 3: Job Object Attributes
    This is the same set of attributes as described in the Print-Job
    response (see section 3.2.1.2).

Hastings, et al. Standards Track [Page 65] RFC 2911 IPP/1.1: Model and Semantics September 2000

3.3.2 Send-URI Operation

 This OPTIONAL operation is identical to the Send-Document operation
 (see section 3.3.1) except that a client MUST supply a URI reference
 ("document-uri" operation attribute) rather than the document data
 itself.  If a Printer object supports this operation, clients can use
 both Send-URI or Send-Document operations to add new documents to an
 existing multi-document Job object.  However, if a client needs to
 indicate that the previous Send-URI or Send-Document was the last
 document,  the client MUST use the Send-Document operation with no
 document data and the "last-document" flag set to 'true' (rather than
 using a Send-URI operation with no "document-uri" operation
 attribute).
 If a Printer object supports this operation, it MUST also support the
 Print-URI operation (see section 3.2.2).
 The Printer object MUST validate the syntax and URI scheme of the
 supplied URI before returning a response, just as in the Print-URI
 operation.  The IPP Printer MAY validate the accessibility of the
 document as part of the operation or subsequently (see section
 3.2.2).

3.3.3 Cancel-Job Operation

 This REQUIRED operation allows a client to cancel a Print Job from
 the time the job is created up to the time it is completed, canceled,
 or aborted.  Since a Job might already be printing by the time a
 Cancel-Job is received, some media sheet pages might be printed
 before the job is actually terminated.
 The IPP object MUST accept or reject the request based on the job's
 current state and transition the job to the indicated new state as
 follows:

Hastings, et al. Standards Track [Page 66] RFC 2911 IPP/1.1: Model and Semantics September 2000

     Current "job-    New "job-     IPP object's response status
         state"         state"             code and action:
    'pending'       'canceled'     'successful-ok'
    'pending-held'  'canceled'     'successful-ok'
    'processing'    'canceled'     'successful-ok'
    'processing'    'processing'   'successful-ok'  See Rule 1
    'processing'    'processing'   'client-error-not-possible'
                                   See Rule 2
    'processing-    'canceled'     'successful-ok'
    stopped'
    'processing-    'processing-   'successful-ok'  See Rule 1
    stopped'        stopped'
    'processing-    'processing-   'client-error-not-possible'
    stopped'        stopped'       See Rule 2
    'completed'     'completed'    'client-error-not-possible'
    'canceled'      'canceled'     'client-error-not-possible'
    'aborted'       'aborted'      'client-error-not-possible'
 Rule 1:  If the implementation requires some measurable time to
 cancel the job in the 'processing' or 'processing-stopped' job
 states, the IPP object MUST add the 'processing-to-stop-point' value
 to the job's "job-state-reasons" attribute and then transition the
 job to the 'canceled' state when the processing ceases (see section
 4.3.8).
 Rule 2:  If the Job object already has the 'processing-to-stop-point'
 value in its "job-state-reasons" attribute, then the Printer object
 MUST reject a Cancel-Job operation.
 Access Rights: The authenticated user (see section 8.3) performing
 this operation must either be the job owner or an operator or
 administrator of the Printer object (see Sections 1 and 8.5).
 Otherwise, the IPP object MUST reject the operation and return:
  'client-error-forbidden', 'client-error-not-authenticated', or
 'client-error-not-authorized' as appropriate.

3.3.3.1 Cancel-Job Request

 The following groups of attributes are part of the Cancel-Job
 Request:
 Group 1: Operation Attributes
    Natural Language and Character Set:
       The "attributes-charset" and "attributes-natural-language"
       attributes as described in section 3.1.4.1.

Hastings, et al. Standards Track [Page 67] RFC 2911 IPP/1.1: Model and Semantics September 2000

    Target:
       Either (1) the "printer-uri" (uri) plus "job-id"
       (integer(1:MAX))or (2) the "job-uri" (uri) operation
       attribute(s) which define the target for this operation as
       described in section 3.1.5.
    Requesting User Name:
       The "requesting-user-name" (name(MAX)) attribute SHOULD be
       supplied by the client as described in section 8.3.
    "message" (text(127)):
       The client OPTIONALLY supplies this attribute.  The Printer
       object OPTIONALLY supports this attribute. It is a message to
       the operator.  This "message" attribute is not the same as the
       "job-message-from-operator" attribute.  That attribute is used
       to report a message from the operator to the end user that
       queries that attribute.  This "message" operation attribute is
       used to send a message from the client to the operator along
       with the operation request.  It is an implementation decision
       of how or where to display this message to the operator (if at
       all).

3.3.3.2 Cancel-Job Response

 The following sets of attributes are part of the Cancel-Job Response:
 Group 1: Operation Attributes
    Status Message:
       In addition to the REQUIRED status code returned in every
       response, the response OPTIONALLY includes a "status-message"
       (text(255)) and/or a "detailed-status-message" (text(MAX))
       operation attribute as described in sections 13 and 3.1.6.
    Natural Language and Character Set:
       The "attributes-charset" and "attributes-natural-language"
       attributes as described in section 3.1.4.2.
 Group 2: Unsupported Attributes
    See section 3.1.7 for details on returning Unsupported Attributes.
 Once a successful response has been sent, the implementation
 guarantees that the Job will eventually end up in the 'canceled'
 state. Between the time of the Cancel-Job operation is accepted and
 when the job enters the 'canceled' job-state (see section 4.3.7), the
 "job-state-reasons" attribute SHOULD contain the 'processing-to-
 stop-point'

Hastings, et al. Standards Track [Page 68] RFC 2911 IPP/1.1: Model and Semantics September 2000

 value which indicates to later queries that although the Job might
 still be 'processing', it will eventually end up in the
 'canceled' state, not the 'completed' state.

3.3.4 Get-Job-Attributes Operation

 This REQUIRED operation allows a client to request the values of
 attributes of a Job object and it is almost identical to the Get-
 Printer-Attributes operation (see section 3.2.5).  The only
 differences are that the operation is directed at a Job object rather
 than a Printer object, there is no "document-format" operation
 attribute used when querying a Job object, and the returned attribute
 group is a set of Job object attributes rather than a set of Printer
 object attributes.
 For Jobs, the possible names of attribute groups are:
  1. 'job-template': the subset of the Job Template attributes that

apply to a Job object (the first column of the table in Section

      4.2) that the implementation supports for Job objects.
    - 'job-description': the subset of the Job Description attributes
      specified in Section 4.3 that the implementation supports for
      Job objects.
    - 'all': the special group 'all' that includes all attributes that
      the implementation supports for Job objects.
 Since a client MAY request specific attributes or named groups, there
 is a potential that there is some overlap.  For example, if a client
 requests, 'job-name' and 'job-description', the client is actually
 requesting the "job-name" attribute once by naming it explicitly, and
 once by inclusion in the 'job-description' group.  In such cases, the
 Printer object NEED NOT return the attribute only once in the
 response even if it is requested multiple times.  The client SHOULD
 NOT request the same attribute in multiple ways.
 It is NOT REQUIRED that a Job object support all attributes belonging
 to a group (since some attributes are OPTIONAL).  However it is
 REQUIRED that each Job object support all these group names.

3.3.4.1 Get-Job-Attributes Request

 The following groups of attributes are part of the Get-Job-Attributes
 Request when the request is directed at a Job object:

Hastings, et al. Standards Track [Page 69] RFC 2911 IPP/1.1: Model and Semantics September 2000

 Group 1: Operation Attributes
    Natural Language and Character Set:
      The "attributes-charset" and "attributes-natural-language"
      attributes as described in section 3.1.4.1.
    Target:
      Either (1) the "printer-uri" (uri) plus "job-id"
      (integer(1:MAX)) or (2) the "job-uri" (uri) operation
      attribute(s) which define the target for this operation as
      described in section 3.1.5.
    Requesting User Name:
      The "requesting-user-name" (name(MAX)) attribute SHOULD be
      supplied by the client as described in section 8.3.
    "requested-attributes" (1setOf keyword):
      The client OPTIONALLY supplies this attribute.  The IPP object
      MUST support this attribute.   It is a set of attribute names
      and/or attribute group names in whose values the requester is
      interested.  If the client omits this attribute, the IPP object
      MUST respond as if this attribute had been supplied with a value
      of 'all'.

3.3.4.2 Get-Job-Attributes Response

 The Printer object returns the following sets of attributes as part
 of the Get-Job-Attributes Response:
 Group 1: Operation Attributes
    Status Message:
       In addition to the REQUIRED status code returned in every
       response, the response OPTIONALLY includes a "status-message"
       (text(255)) and/or a "detailed-status-message" (text(MAX))
       operation attribute as described in sections 13 and 3.1.6.
    Natural Language and Character Set:
       The "attributes-charset" and "attributes-natural-language"
       attributes as described in section 3.1.4.2.  The "attributes-
       natural-language" MAY be the natural language of the Job
       object, rather than the one requested.
 Group 2: Unsupported Attributes
    See section 3.1.7 for details on returning Unsupported Attributes.

Hastings, et al. Standards Track [Page 70] RFC 2911 IPP/1.1: Model and Semantics September 2000

    The response NEED NOT contain the "requested-attributes" operation
    attribute with any supplied values (attribute keywords) that were
    requested by the client but are not supported by the IPP object.
    If the Printer object does return unsupported attributes
    referenced in the "requested-attributes" operation attribute and
    that attribute included group names, such as 'all', the
    unsupported attributes MUST NOT include attributes described in
    the standard but not supported by the implementation.
 Group 3: Job Object Attributes
    This is the set of requested attributes and their current values.
    The IPP object ignores (does not respond with) any requested
    attribute or value which is not supported or which is restricted
    by the security policy in force, including whether the requesting
    user is the user that submitted the job (job originating user) or
    not (see section 8).  However, the IPP object MUST respond with
    the 'unknown' value for any supported attribute (including all
    REQUIRED attributes) for which the IPP object does not know the
    value, unless it would violate the security policy.  See the
    description of the "out-of-band" values in the beginning of
    Section 4.1.

3.3.5 Hold-Job Operation

 This OPTIONAL operation allows a client to hold a pending job in the
 queue so that it is not eligible for scheduling.  If the Hold-Job
 operation is supported, then the Release-Job operation MUST be
 supported, and vice-versa.  The OPTIONAL "job-hold-until" operation
 attribute allows a client to specify whether to hold the job
 indefinitely or until a specified time period, if supported.
 The IPP object MUST accept or reject the request based on the job's
 current state and transition the job to the indicated new state as
 follows:

Hastings, et al. Standards Track [Page 71] RFC 2911 IPP/1.1: Model and Semantics September 2000

      Current "job-     New "job-state"   IPP object's response status
          state"                                 code and action:
    'pending'         'pending-held'     'successful-ok'  See Rule 1
    'pending'         'pending'          'successful-ok'  See Rule 2
    'pending-held'    'pending-held'     'successful-ok'  See Rule 1
    'pending-held'    'pending'          'successful-ok'  See Rule 2
    'processing'      'processing'       'client-error-not-possible'
    'processing-      'processing-       'client-error-not-possible'
    stopped'          stopped'
    'completed'       'completed'        'client-error-not-possible'
    'canceled'        'canceled'         'client-error-not-possible'
    'aborted'         'aborted'          'client-error-not-possible'
 Rule 1:  If the implementation supports multiple reasons for a job to
 be in the 'pending-held' state, the IPP object MUST add the 'job-
 hold-until-specified' value to the job's "job-state-reasons"
 attribute.
 Rule 2:  If the IPP object supports the "job-hold-until" operation
 attribute, but the specified time period has already started (or is
 the 'no-hold' value) and there are no other reasons to hold the job,
 the IPP object MUST make the job be a candidate for processing
 immediately (see Section 4.2.2) by putting the job in the 'pending'
 state.
 Note:  In order to keep the Hold-Job operation simple, such a request
 is rejected when the job is in the 'processing' or 'processing-
 stopped' states.  If an operation is needed to hold jobs while in
 these states, it will be added as an additional operation, rather
 than overloading the Hold-Job operation.  Then it is clear to clients
 by querying the Printer object's "operations-supported" (see Section
 4.4.15) and the Job object's "job-state" (see Section 4.3.7)
 attributes which operations are possible.
 Access Rights: The authenticated user (see section 8.3) performing
 this operation must either be the job owner or an operator or
 administrator of the Printer object (see Sections 1 and 8.5).
 Otherwise, the IPP object MUST reject the operation and return:
 'client-error-forbidden', 'client-error-not-authenticated', or
 'client-error-not-authorized' as appropriate.

3.3.5.1 Hold-Job Request

 The groups and operation attributes are the same as for a Cancel-Job
 request (see section 3.3.3.1), with the addition of the following
 Group 1 Operation attribute:

Hastings, et al. Standards Track [Page 72] RFC 2911 IPP/1.1: Model and Semantics September 2000

    "job-hold-until" (type3 keyword | name(MAX)):
       The client OPTIONALLY supplies this Operation attribute.  The
       IPP object MUST support this operation attribute in a Hold-Job
       request, if it supports the "job-hold-until" Job template
       attribute in create operations.  See section 4.2.2.  The IPP
       object SHOULD support the "job-hold-until" Job Template
       attribute for use in job create operations with at least the
       'indefinite' value, if it supports the Hold-Job operation.
       Otherwise, a client cannot create a job and hold it immediately
       (without picking some supported time period in the future).
       If supplied and supported as specified in the Printer's "job-
       hold-until-supported" attribute, the IPP object copies the
       supplied operation attribute to the Job object, replacing the
       job's previous "job-hold-until" attribute, if present, and
       makes the job a candidate for scheduling during the supplied
       named time period.
       If supplied, but either the "job-hold-until" Operation
       attribute itself or the value supplied is not supported, the
       IPP object accepts the request, returns the unsupported
       attribute or value in the Unsupported Attributes Group
       according to section 3.1.7, returns the 'successful-ok-
       ignored-or-substituted-attributes, and holds the job
       indefinitely until a client performs a subsequent Release-Job
       operation.
       If the client (1) supplies a value that specifies a time period
       that has already started or the 'no-hold' value (meaning don't
       hold the job) and (2) the IPP object supports the "job-hold-
       until" operation attribute and there are no other reasons to
       hold the job, the IPP object MUST accept the operation and make
       the job be a candidate for processing immediately (see Section
       4.2.2).
       If the client does not supply a "job-hold-until" Operation
       attribute in the request, the IPP object MUST populate the job
       object with a "job-hold-until" attribute with the 'indefinite'
       value (if IPP object supports the "job-hold-until" attribute)
       and hold the job indefinitely, until a client performs a
       Release-Job operation.

3.3.5.2 Hold-Job Response

 The groups and attributes are the same as for a Cancel-Job response
 (see section 3.3.3.2).

Hastings, et al. Standards Track [Page 73] RFC 2911 IPP/1.1: Model and Semantics September 2000

3.3.6 Release-Job Operation

 This OPTIONAL operation allows a client to release a previously held
 job so that it is again eligible for scheduling.  If the Hold-Job
 operation is supported, then the Release-Job operation MUST be
 supported, and vice-versa.
 This operation removes the "job-hold-until" job attribute, if
 present, from the job object that had been supplied in the create or
 most recent Hold-Job or Restart-Job operation and removes its effect
 on the job.  The IPP object MUST remove the 'job-hold-until-
 specified' value from the job's "job-state-reasons" attribute, if
 present.  See section 4.3.8.
 The IPP object MUST accept or reject the request based on the job's
 current state and transition the job to the indicated new state as
 follows:
      Current "job-   New "job-state"    IPP object's response status
         state"                                code and action:
    'pending'        'pending'        'successful-ok'
                                       No effect on the job.
    'pending-held'   'pending-held'   'successful-ok'  See Rule 1
    'pending-held'   'pending'        'successful-ok'
    'processing'     'processing'     'successful-ok'
                                       No effect on the job.
    'processing-     'processing-     'successful-ok'
     stopped'         stopped'         No effect on the job.
    'completed'      'completed'      'client-error-not-possible'
    'canceled'       'canceled'       'client-error-not-possible'
    'aborted'        'aborted'        'client-error-not-possible'
 Rule 1:  If there are other reasons to keep the job in the 'pending-
 held' state, such as 'resources-are-not-ready', the job remains in
 the 'pending-held' state.  Thus the 'pending-held' state is not just
 for jobs that have the 'job-hold-until' applied to them, but are for
 any reason to keep the job from being a candidate for scheduling and
 processing, such as 'resources-are-not-ready'.  See the "job-hold-
 until" attribute (section 4.2.2).
 Access Rights: The authenticated user (see section 8.3) performing
 this operation must either be the job owner or an operator or
 administrator of the Printer object (see Sections 1 and 8.5).
 Otherwise, the IPP object MUST reject the operation and return:
 'client-error-forbidden', 'client-error-not-authenticated', or
 'client-error-not-authorized' as appropriate.

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 The Release-Job Request and Release-Job Response have the same
 attribute groups and attributes as the Cancel-Job operation (see
 section 3.3.3.1 and 3.3.3.2).

3.3.7 Restart-Job Operation

 This OPTIONAL operation allows a client to restart a job that is
 retained in the queue after processing has completed (see section
 4.3.7.2).
 The job is moved to the 'pending' or 'pending-held' job state and
 restarts at the beginning on the same IPP Printer object with the
 same attribute values.  If any of the documents in the job were
 passed by reference (Print-URI or Send-URI), the Printer MUST re-
 fetch the data, since the semantics of Restart-Job are to repeat all
 Job processing.  The Job Description attributes that accumulate job
 progress, such as "job-impressions-completed", "job-media-sheets-
 completed", and "job-k-octets-processed", MUST be reset to 0 so that
 they give an accurate record of the job from its restart point.  The
 job object MUST continue to use the same "job-uri" and "job-id"
 attribute values.
 Note:  If in the future an operation is needed that does not reset
 the job progress attributes, then a new operation will be defined
 which makes a copy of the job, assigns a new "job-uri" and "job-id"
 to the copy and resets the job progress attributes in the new copy
 only.
 The IPP object MUST accept or reject the request based on the job's
 current state, transition the job to the indicated new state as
 follows:

Hastings, et al. Standards Track [Page 75] RFC 2911 IPP/1.1: Model and Semantics September 2000

      Current "job-   New "job-state"    IPP object's response status
         state"                                code and action:
    'pending'        'pending'        'client-error-not-possible'
    'pending-held'   'pending-held'   'client-error-not-possible'
    'processing'     'processing'     'client-error-not-possible'
    'processing-     'processing-     'client-error-not-possible'
    stopped'         stopped'
    'completed'      'pending' or     'successful-ok' - job is started
                      'pending-held'   over.
    'completed'      'completed'      'client-error-not-possible' -
                                       see Rule 1
    'canceled'       'pending' or     'successful-ok' - job is started
                      'pending-held'   over.
    'canceled'       'canceled'       'client-error-not-possible' -
                                       see Rule 1
    'aborted'        'pending' or     'successful-ok' - job is started
                      'pending-held'   over.
    'aborted'        'aborted'        'client-error-not-possible' -
                                       see Rule 1
 Rule 1:  If the Job Retention Period has expired for the job in this
 state, then the IPP object rejects the operation.  See section
 4.3.7.2.
 Note:  In order to prevent a user from inadvertently restarting a job
 in the middle, the Restart-Job request is rejected when the job is in
 the 'processing' or 'processing-stopped' states.  If in the future an
 operation is needed to hold or restart jobs while in these states, it
 will be added as an additional operation, rather than overloading the
 Restart-Job operation, so that it is clear that the user intended
 that the current job not be completed.
 Access Rights: The authenticated user (see section 8.3) performing
 this operation must either be the job owner or an operator or
 administrator of the Printer object (see Sections 1 and 8.5).
 Otherwise, the IPP object MUST reject the operation and return:
 'client-error-forbidden', 'client-error-not-authenticated', or
 'client-error-not-authorized' as appropriate.

3.3.7.1 Restart-Job Request

 The groups and attributes are the same as for a Cancel-Job request
 (see section 3.3.3.1), with the addition of the following Group 1
 Operation attribute:

Hastings, et al. Standards Track [Page 76] RFC 2911 IPP/1.1: Model and Semantics September 2000

    "job-hold-until" (type3 keyword | name(MAX)):
       The client OPTIONALLY supplies this attribute.  The IPP object
       MUST support this Operation attribute in a Restart-Job request,
       if it supports the "job-hold-until" Job Template attribute in
       create operations.  See section 4.2.2.  Otherwise, the IPP
       object NEED NOT support the "job-hold-until" Operation
       attribute in a Restart-Job request.
       If supplied and supported as specified in the Printer's "job-
       hold-until-supported" attribute, the IPP object copies the
       supplied Operation attribute to the Job object, replacing the
       job's previous "job-hold-until" attribute, if present, and
       makes the job a candidate for scheduling during the supplied
       named time period.  See section 4.2.2.
       If supplied, but the value is not supported, the IPP object
       accepts the request, returns the unsupported attribute or value
       in the Unsupported Attributes Group according to section 3.1.7,
       returns the 'successful-ok-ignored-or-substituted-attributes'
       status code, and holds the job indefinitely until a client
       performs a subsequent Release-Job operation.
       If supplied, but the "job-hold-until" Operation attribute
       itself is not supported, the IPP object accepts the request,
       returns the unsupported attribute with the out-of-band
       'unsupported' value in the Unsupported Attributes Group
       according to section 3.1.7, returns the 'successful-ok-
       ignored-or-substituted-attributes' status code, and restarts
       the job, i.e., ignores the "job-hold-until" attribute.
       If the client (1) supplies a value that specifies a time period
       that has already started or the 'no-hold' value (meaning don't
       hold the job) and (2) the IPP object supports the "job-hold-
       until" operation attribute and there are no other reasons to
       hold the job, the IPP object makes the job a candidate for
       processing immediately (see Section 4.2.2).
       If the client does not supply a "job-hold-until" operation
       attribute in the request, the IPP object removes the "job-
       hold-until" attribute, if present, from the job.  If there are
       no other reasons to hold the job, the Restart-Job operation
       makes the job a candidate for processing immediately (see
       Section 4.2.2).

Hastings, et al. Standards Track [Page 77] RFC 2911 IPP/1.1: Model and Semantics September 2000

3.3.7.2 Restart-Job Response

 The groups and attributes are the same as for a Cancel-Job response
 (see section 3.3.3.2).
 Note:  In the future an OPTIONAL Modify-Job or Set-Job-Attributes
 operation may be specified that allows the client to modify other
 attributes before releasing the restarted job.

4. Object Attributes

 This section describes the attributes with their corresponding
 attribute syntaxes and values that are part of the IPP model.  The
 sections below show the objects and their associated attributes which
 are included within the scope of this protocol.  Many of these
 attributes are derived from other relevant documents:
  1. Document Printing Application (DPA) [ISO10175]
  2. RFC 1759 Printer MIB [RFC1759]
 Each attribute is uniquely identified in this document using a
 "keyword" (see section 12.2.1) which is the name of the attribute.
 The keyword is included in the section header describing that
 attribute.
 Note:  Not only are keywords used to identify attributes, but one of
 the attribute syntaxes described below is "keyword" so that some
 attributes have keyword values.  Therefore, these attributes are
 defined as having an attribute syntax that is a set of keywords.

4.1 Attribute Syntaxes

 This section defines the basic attribute syntax types that all
 clients and IPP objects MUST be able to accept in responses and
 accept in requests, respectively.  Each attribute description in
 sections 3 and 4 includes the name of attribute syntax(es) in the
 heading (in parentheses).  A conforming implementation of an
 attribute MUST include the semantics of the attribute syntax(es) so
 identified.  Section 6.3 describes how the protocol can be extended
 with new attribute syntaxes.
 The attribute syntaxes are specified in the following sub-sections,
 where the sub-section heading is the keyword name of the attribute
 syntax inside the single quotes.  In operation requests and responses
 each attribute value MUST be represented as one of the attribute
 syntaxes specified in the sub-section heading for the attribute.  In
 addition, the value of an attribute in a response (but not in a

Hastings, et al. Standards Track [Page 78] RFC 2911 IPP/1.1: Model and Semantics September 2000

 request) MAY be one of the "out-of-band" values whose special
 encoding rules are defined in the "Encoding and Transport" document
 [RFC2910].   Standard "out-of-band" values are:
    'unknown': The attribute is supported by the IPP object, but the
       value is unknown to the IPP object for some reason.
    'unsupported': The attribute is unsupported by the IPP object.
       This value MUST be returned only as the value of an attribute
       in the Unsupported Attributes Group.
    'no-value': The attribute is supported by the Printer object, but
       the administrator has not yet configured a value.
 All attributes in a request MUST have one or more values as defined
 in Sections 4.2 to 4.4.  Thus clients MUST NOT supply attributes with
 "out-of-band" values for operations defined in this document.  All
 attributes in a response MUST have one or more values as defined in
 Sections 4.2 to 4.4 or a single "out-of-band" value.
 Most attributes are defined to have a single attribute syntax.
 However, a few attributes (e.g., "job-sheet", "media", "job-hold-
 until") are defined to have several attribute syntaxes, depending on
 the value.  These multiple attribute syntaxes are separated by the
 "|" character in the sub-section heading to indicate the choice.
 Since each value MUST be tagged as to its attribute syntax in the
 protocol, a single-valued attribute instance may have any one of its
 attribute syntaxes and a multi-valued attribute instance may have a
 mixture of its defined attribute syntaxes.

4.1.1 'text'

 A text attribute is an attribute whose value is a sequence of zero or
 more characters encoded in a maximum of 1023 ('MAX') octets.  MAX is
 the maximum length for each value of any text attribute.  However, if
 an attribute will always contain values whose maximum length is much
 less than MAX, the definition of that attribute will include a
 qualifier that defines the maximum length for values of that
 attribute.  For example:  the "printer-location" attribute is
 specified as "printer-location (text(127))".  In this case, text
 values for "printer-location" MUST NOT exceed 127 octets; if supplied
 with a longer text string via some external interface (other than the
 protocol), implementations are free to truncate to this shorter
 length limitation.
 In this document, all text attributes are defined using the 'text'
 syntax.  However, 'text' is used only for brevity; the formal
 interpretation of 'text' is: 'textWithoutLanguage |
 textWithLanguage'.  That is, for any attribute defined in this
 document using the 'text' attribute syntax, all IPP objects and

Hastings, et al. Standards Track [Page 79] RFC 2911 IPP/1.1: Model and Semantics September 2000

 clients MUST support both the 'textWithoutLanguage' and
 'textWithLanguage' attribute syntaxes.  However, in actual usage and
 protocol execution, objects and clients accept and return only one of
 the two syntax per attribute.  The syntax 'text' never appears "on-
 the-wire".
 Both 'textWithoutLanguage' and 'textWithLanguage' are needed to
 support the real world needs of interoperability between sites and
 systems that use different natural languages as the basis for human
 communication.  Generally, one natural language applies to all text
 attributes in a given request or response. The language is indicated
 by the "attributes-natural-language" operation attribute defined in
 section 3.1.4 or "attributes-natural-language" job attribute defined
 in section 4.3.20, and there is no need to identify the natural
 language for each text string on a value-by-value basis.  In these
 cases, the attribute syntax 'textWithoutLanguage' is used for text
 attributes.  In other cases, the client needs to supply or the
 Printer object needs to return a text value in a natural language
 that is different from the rest of the text values in the request or
 response.  In these cases, the client or Printer object uses the
 attribute syntax 'textWithLanguage' for text attributes (this is the
 Natural Language Override mechanism described in section 3.1.4).
 The 'textWithoutLanguage' and 'textWithLanguage' attribute syntaxes
 are described in more detail in the following sections.

4.1.1.1 'textWithoutLanguage'

 The 'textWithoutLanguage' syntax indicates a value that is sequence
 of zero or more characters encoded in a maximum of 1023 (MAX) octets.
 Text strings are encoded using the rules of some charset.  The
 Printer object MUST support the UTF-8 charset [RFC2279] and MAY
 support additional charsets to represent 'text' values, provided that
 the charsets are registered with IANA [IANA-CS].  See Section 4.1.7
 for the definition of the 'charset' attribute syntax, including
 restricted semantics and examples of charsets.

4.1.1.2 'textWithLanguage'

 The 'textWithLanguage' attribute syntax is a compound attribute
 syntax consisting of two parts: a 'textWithoutLanguage' part encoded
 in a maximum of 1023 (MAX) octets plus an additional
 'naturalLanguage' (see section 4.1.8) part that overrides the natural
 language in force.  The 'naturalLanguage' part explicitly identifies
 the natural language that applies to the text part of that value and
 that value alone.  For any give text attribute, the
 'textWithoutLanguage' part is limited to the maximum length defined
 for that 'text' attribute, and the 'naturalLanguage' part is always

Hastings, et al. Standards Track [Page 80] RFC 2911 IPP/1.1: Model and Semantics September 2000

 limited to 63 (additional) octets.  Using the 'textWithLanguage'
 attribute syntax rather than the normal 'textWithoutLanguage' syntax
 is the so-called Natural Language Override mechanism and MUST be
 supported by all IPP objects and clients.
 If the attribute is multi-valued (1setOf text), then the
 'textWithLanguage' attribute syntax MUST be used to explicitly
 specify each attribute value whose natural language needs to be
 overridden.  Other values in a multi-valued 'text' attribute in a
 request or a response revert to the natural language of the operation
 attribute.
 In a create request, the Printer object MUST accept and store with
 the Job object any natural language in the "attributes-natural-
 language" operation attribute, whether the Printer object supports
 that natural language or not.  Furthermore, the Printer object MUST
 accept and store any 'textWithLanguage' attribute value, whether the
 Printer object supports that natural language or not.  These
 requirements are independent of the value of the "ipp-attribute-
 fidelity" operation attribute that the client MAY supply.
 Example:  If the client supplies the "attributes-natural-language"
 operation attribute with the value: 'en' indicating English, but the
 value of the "job-name" attribute is in French, the client MUST use
 the 'textWithLanguage' attribute syntax with the following two
 values:
    'fr': Natural Language Override indicating French
    'Rapport Mensuel': the job name in French
 See the "Encoding and Transport" document [RFC2910] section 3.9 for
 the encoding of the two parts and Appendix A for a detailed example
 of the 'textWithLanguage' attribute syntax.

4.1.2 'name'

 This syntax type is used for user-friendly strings, such as a Printer
 name, that, for humans, are more meaningful than identifiers.  Names
 are never translated from one natural language to another.  The
 'name' attribute syntax is essentially the same as 'text', including
 the REQUIRED support of UTF-8 except that the sequence of characters
 is limited so that its encoded form MUST NOT exceed 255 (MAX) octets.
 Also like 'text', 'name' is really an abbreviated notation for either
 'nameWithoutLanguage' or 'nameWithLanguage'.  That is, all IPP
 objects and clients MUST support both the 'nameWithoutLanguage' and
 'nameWithLanguage' attribute syntaxes.  However, in actual usage and

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 protocol execution, objects and clients accept and return only one of
 the two syntax per attribute.  The syntax 'name' never appears "on-
 the-wire".
 Only the 'text' and 'name' attribute syntaxes permit the Natural
 Language Override mechanism.
 Some attributes are defined as 'type3 keyword | name'.  These
 attributes support values that are either type3 keywords or names.
 This dual-syntax mechanism enables a site administrator to extend
 these attributes to legally include values that are locally defined
 by the site administrator.  Such names are not registered with IANA.

4.1.2.1 'nameWithoutLanguage'

 The 'nameWithoutLanguage' syntax indicates a value that is sequence
 of zero or more characters encoded in a maximum of 255 (MAX) octets.

4.1.2.2 'nameWithLanguage'

 The 'nameWithLanguage' attribute syntax is a compound attribute
 syntax consisting of two parts: a 'nameWithoutLanguage' part encoded
 in a maximum of 1023 (MAX) octets plus an additional
 'naturalLanguage' (see section 4.1.8) part that overrides the natural
 language in force.  The 'naturalLanguage' part explicitly identifies
 the natural language that applies to that name value and that name
 value alone.  For any give text attribute, the 'textWithoutLanguage'
 part is limited to the maximum length defined for that 'text'
 attribute, and the 'naturalLanguage' part is always limited to 63
 (additional) octets.  Using the 'textWithLanguage' attribute syntax
 rather than the normal 'textWithoutLanguage' syntax is the so-called
 Natural Language Override mechanism and MUST be supported by all IPP
 objects and clients.
 The 'nameWithLanguage' attribute syntax behaves the same as the
 'textWithLanguage' syntax.  Using the 'textWithLanguage' attribute
 syntax rather than the normal 'textWithoutLanguage' syntax is the
 so-called Natural Language Override mechanism and MUST be supported
 by all IPP objects and clients.  If a name is in a language that is
 different than the rest of the object or operation, then this
 'nameWithLanguage' syntax is used rather than the generic
 'nameWithoutLanguage' syntax.
 If the attribute is multi-valued (1setOf text), then the
 'nameWithLanguage' attribute syntax MUST be used to explicitly
 specify each attribute value whose natural language needs to be
 overridden.

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 Other values in a multi-valued 'name' attribute in a request or a
 response revert to the natural language of the operation attribute.
 In a create request, the Printer object MUST accept and store with
 the Job object any natural language in the "attributes-natural-
 language" operation attribute, whether the Printer object supports
 that natural language or not.  Furthermore, the Printer object MUST
 accept and store any 'nameWithLanguage' attribute value, whether the
 Printer object supports that natural language or not.  These
 requirements are independent of the value of the "ipp-attribute-
 fidelity" operation attribute that the client MAY supply.
 Example:  If the client supplies the "attributes-natural-language"
 operation attribute with the value:  'en' indicating English, but the
 "printer-name" attribute is in German, the client MUST use the
 'nameWithLanguage' attribute syntax as follows:
    'de':  Natural Language Override indicating German
    'Farbdrucker':  the Printer name in German
 See the "Encoding and Transport" document [RFC2910] section 3.9 for
 the encoding of the two parts and Appendix A for a detailed example
 of the 'nameWithLanguage' attribute syntax.

4.1.2.3 Matching 'name' attribute values

 For purposes of matching two 'name' attribute values for equality,
 such as in job validation (where a client-supplied value for
 attribute "xxx" is checked to see if the value is among the values of
 the Printer object's corresponding "xxx-supported" attribute), the
 following match rules apply:
    1. 'keyword' values never match 'name' values.
    2. 'name' (nameWithoutLanguage and nameWithLanguage) values match
       if (1) the name parts match and (2) the Associated Natural-
       Language parts (see section 3.1.4.1) match.  The matching rules
       are:
       a. the name parts match if the two names are identical
          character by character, except it is RECOMMENDED that case
          be ignored.  For example: 'Ajax-letter-head-white' MUST
          match 'Ajax-letter-head-white' and SHOULD match 'ajax-
          letter-head-white' and 'AJAX-LETTER-HEAD-WHITE'.

Hastings, et al. Standards Track [Page 83] RFC 2911 IPP/1.1: Model and Semantics September 2000

       b. the Associated Natural-Language parts match if the shorter
          of the two meets the syntactic requirements of RFC 1766
          [RFC1766] and matches byte for byte with the longer.  For
          example, 'en' matches 'en', 'en-us' and 'en-gb', but matches
          neither 'fr' nor 'e'.

4.1.3 'keyword'

 The 'keyword' attribute syntax is a sequence of characters, length: 1
 to 255, containing only the US-ASCII [ASCII] encoded values for
 lowercase letters ("a" - "z"), digits ("0" - "9"), hyphen ("-"), dot
 ("."), and underscore ("_").  The first character MUST be a lowercase
 letter.  Furthermore, keywords MUST be in U.S. English.
 This syntax type is used for enumerating semantic identifiers of
 entities in the abstract protocol, i.e., entities identified in this
 document.  Keywords are used as attribute names or values of
 attributes.  Unlike 'text' and 'name' attribute values, 'keyword'
 values MUST NOT use the Natural Language Override mechanism, since
 they MUST always be US-ASCII and U.S. English.
 Keywords are for use in the protocol.  A user interface will likely
 provide a mapping between protocol keywords and displayable user-
 friendly words and phrases which are localized to the natural
 language of the user.  While the keywords specified in this document
 MAY be displayed to users whose natural language is U.S. English,
 they MAY be mapped to other U.S. English words for U.S. English
 users, since the user interface is outside the scope of this
 document.
 In the definition for each attribute of this syntax type, the full
 set of defined keyword values for that attribute are listed.
 When a keyword is used to represent an attribute (its name), it MUST
 be unique within the full scope of all IPP objects and attributes.
 When a keyword is used to represent a value of an attribute, it MUST
 be unique just within the scope of that attribute.  That is, the same
 keyword MUST NOT be used for two different values within the same
 attribute to mean two different semantic ideas.  However, the same
 keyword MAY be used across two or more attributes, representing
 different semantic ideas for each attribute.  Section 6.1 describes
 how the protocol can be extended with new keyword values.  Examples
 of attribute name keywords:
    "job-name"
    "attributes-charset"

Hastings, et al. Standards Track [Page 84] RFC 2911 IPP/1.1: Model and Semantics September 2000

 Note:  This document uses "type1", "type2", and "type3" prefixes to
 the "keyword" basic syntax to indicate different levels of review for
 extensions (see section 6.1).

4.1.4 'enum'

 The 'enum' attribute syntax is an enumerated integer value that is in
 the range from 1 to 2**31 - 1 (MAX).   Each value has an associated
 'keyword' name.  In the definition for each attribute of this syntax
 type, the full set of possible values for that attribute are listed.
 This syntax type is used for attributes for which there are enum
 values assigned by other standards, such as SNMP MIBs.  A number of
 attribute enum values in this document are also used for
 corresponding attributes in other standards [RFC1759].  This syntax
 type is not used for attributes to which the administrator may assign
 values.  Section 6.1 describes how the protocol can be extended with
 new enum values.
 Enum values are for use in the protocol.  A user interface will
 provide a mapping between protocol enum values and displayable user-
 friendly words and phrases which are localized to the natural
 language of the user.  While the enum symbols specified in this
 document MAY be displayed to users whose natural language is U.S.
 English, they MAY be mapped to other U.S. English words for U.S.
 English users, since the user interface is outside the scope of this
 document.
 Note: SNMP MIBs use '2' for 'unknown' which corresponds to the IPP
 "out-of-band" value 'unknown'.  See the description of the "out-of-
 band" values at the beginning of Section 4.1.  Therefore, attributes
 of type 'enum' start at '3'.
 Note:  This document uses "type1", "type2", and "type3" prefixes to
 the "enum" basic syntax to indicate different levels of review for
 extensions (see section 6.1).

4.1.5 'uri'

 The 'uri' attribute syntax is any valid Uniform Resource Identifier
 or URI [RFC2396].  Most often, URIs are simply Uniform Resource
 Locators or URLs.  The maximum length of URIs used as values of IPP
 attributes is 1023 octets.  Although most other IPP attribute syntax
 types allow for only lower-cased values, this attribute syntax type
 conforms to the case-sensitive and case-insensitive rules specified
 in [RFC2396].  See also [IPP-IIG] for a discussion of case in URIs.

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4.1.6 'uriScheme'

 The 'uriScheme' attribute syntax is a sequence of characters
 representing a URI scheme according to RFC 2396 [RFC2396].  Though
 RFC 2396 requires that the values be case-insensitive, IPP requires
 all lower case values in IPP attributes to simplify comparing by IPP
 clients and Printer objects.
 Standard values for this syntax type are the following keywords:
    'ipp':  for IPP schemed URIs (e.g., "ipp:...")
    'http':  for HTTP schemed URIs (e.g., "http:...")
    'https':  for use with HTTPS schemed URIs (e.g., "https:...") (not
       on IETF standards track)
    'ftp': for FTP schemed URIs (e.g., "ftp:...")
    'mailto': for SMTP schemed URIs (e.g., "mailto:...")
    'file': for file schemed URIs (e.g., "file:...")
 A Printer object MAY support any URI 'scheme' that has been
 registered with IANA [IANA-MT]. The maximum length of URI 'scheme'
 values used to represent IPP attribute values is 63 octets.

4.1.7 'charset'

 The 'charset' attribute syntax is a standard identifier for a
 charset.  A charset is a coded character set and encoding scheme.
 Charsets are used for labeling certain document contents and 'text'
 and 'name' attribute values.  The syntax and semantics of this
 attribute syntax are specified in RFC 2046 [RFC2046] and contained in
 the IANA character-set Registry [IANA-CS] according to the IANA
 procedures [RFC2278].  Though RFC 2046 requires that the values be
 case-insensitive US-ASCII [ASCII], IPP requires all lower case values
 in IPP attributes to simplify comparing by IPP clients and Printer
 objects.  When a character-set in the IANA registry has more than one
 name (alias), the name labeled as "(preferred MIME name)", if
 present, MUST be used.
 The maximum length of 'charset' values used to represent IPP
 attribute values is 63 octets.
 Some examples are:
    'utf-8':  ISO 10646 Universal Multiple-Octet Coded Character Set
       (UCS) represented as the UTF-8 [RFC2279] transfer encoding
       scheme in which US-ASCII is a subset charset.
    'us-ascii':  7-bit American Standard Code for Information
       Interchange (ASCII), ANSI X3.4-1986 [ASCII].  That standard

Hastings, et al. Standards Track [Page 86] RFC 2911 IPP/1.1: Model and Semantics September 2000

       defines US-ASCII, but RFC 2045 [RFC2045] eliminates most of the
       control characters from conformant usage in MIME and IPP.
    'iso-8859-1':  8-bit One-Byte Coded Character Set, Latin Alphabet
       Nr 1 [ISO8859-1].  That standard defines a coded character set
       that is used by Latin languages in the Western Hemisphere and
       Western Europe.  US-ASCII is a subset charset.
 Some attribute descriptions MAY place additional requirements on
 charset values that may be used, such as REQUIRED values that MUST be
 supported or additional restrictions, such as requiring that the
 charset have US- ASCII as a subset charset.

4.1.8 'naturalLanguage'

 The 'naturalLanguage' attribute syntax is a standard identifier for a
 natural language and optionally a country.  The values for this
 syntax type are defined by RFC 1766 [RFC1766].  Though RFC 1766
 requires that the values be case-insensitive US-ASCII [ASCII], IPP
 requires all lower case to simplify comparing by IPP clients and
 Printer objects.  Examples include:
    'en':  for English
    'en-us': for US English
    'fr': for French
    'de':  for German
 The maximum length of 'naturalLanguage' values used to represent IPP
 attribute values is 63 octets.

4.1.9 'mimeMediaType'

 The 'mimeMediaType' attribute syntax is the Internet Media Type
 (sometimes called MIME type) as defined by RFC 2046 [RFC2046] and
 registered according to the procedures of RFC 2048 [RFC2048] for
 identifying a document format.  The value MAY include a charset, or
 other, parameter, depending on the specification of the Media Type in
 the IANA Registry [IANA-MT].  Although most other IPP syntax types
 allow for only lower-cased values, this syntax type allows for
 mixed-case values which are case-insensitive.
 Examples are:
    'text/html': An HTML document
    'text/plain': A plain text document in US-ASCII (RFC 2046
       indicates that in the absence of the charset parameter MUST
       mean US-ASCII rather than simply unspecified) [RFC2046].
    'text/plain; charset=US-ASCII':  A plain text document in US-ASCII
       [52, 56].

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    'text/plain; charset=ISO-8859-1':  A plain text document in ISO
       8859-1 (Latin 1) [ISO8859-1].
    'text/plain; charset=utf-8':  A plain text document in ISO 10646
       represented as UTF-8 [RFC2279]
    'application/postscript':  A PostScript document [RFC2046]
    'application/vnd.hp-PCL':  A PCL document [IANA-MT] (charset
       escape sequence embedded in the document data)
    'application/pdf':  Portable Document Format - see IANA MIME Media
       Type registry
    'application/octet-stream': Auto-sense - see section 4.1.9.1
 The maximum length of a 'mimeMediaType' value to represent IPP
 attribute values is 255 octets.

4.1.9.1 Application/octet-stream – Auto-Sensing the document format

 One special type is 'application/octet-stream'.  If the Printer
 object supports this value, the Printer object MUST be capable of
 auto-sensing the format of the document data using an
 implementation-dependent method that examines some number of octets
 of the document data, either as part of the create operation and/or
 at document processing time.  During auto-sensing, a Printer may
 determine that the document-data has a format that the Printer
 doesn't recognize.  If the Printer determines this problem before
 returning an operation response, it rejects the request and returns
 the 'client-error-document-format-not-supported' status code.  If the
 Printer determines this problem after accepting the request and
 returning an operation response with one of the successful status
 codes, the Printer adds the 'unsupported-document-format' value to
 the job's "job-state-reasons" attribute.
 If the Printer object's default value attribute "document-format-
 default" is set to 'application/octet-stream', the Printer object not
 only supports auto-sensing of the document format, but will depend on
 the result of applying its auto-sensing when the client does not
 supply the "document-format" attribute.  If the client supplies a
 document format value, the Printer MUST rely on the supplied
 attribute, rather than trust its auto-sensing algorithm.  To
 summarize:
    1. If the client does not supply a document format value, the
       Printer MUST rely on its default value setting (which may be
       'application/octet-stream' indicating an auto-sensing
       mechanism).
    2. If the client supplies a value other than 'application/octet-
       stream', the client is supplying valid information about the
       format of the document data and the Printer object MUST trust
       the client supplied value more than the outcome of applying an

Hastings, et al. Standards Track [Page 88] RFC 2911 IPP/1.1: Model and Semantics September 2000

       automatic format detection mechanism.  For example, the client
       may be requesting the printing of a PostScript file as a
       'text/plain' document.  The Printer object MUST print a text
       representation of the PostScript commands rather than interpret
       the stream of PostScript commands and print the result.
    3. If the client supplies a value of 'application/octet-stream',
       the client is indicating that the Printer object MUST use its
       auto-sensing mechanism on the client supplied document data
       whether auto-sensing is the Printer object's default or not.
 Note:  Since the auto-sensing algorithm is probabilistic, if the
 client requests both auto-sensing ("document-format" set to
 'application/octet-stream') and true fidelity ("ipp-attribute-
 fidelity" set to 'true'), the Printer object might not be able to
 guarantee exactly what the end user intended (the auto-sensing
 algorithm might mistake one document format for another), but it is
 able to guarantee that its auto-sensing mechanism be used.
 When a Printer performs auto-sensing of a document in a submitted
 job, it is RECOMMENDED that the Printer indicate to the user that
 such auto-sensing has occurred and which document-format was auto-
 sensed by printing that information on the job's job-start-sheet.

4.1.10 'octetString'

 The 'octetString' attribute syntax is a sequence of octets encoded in
 a maximum of 1023 octets which is indicated in sub-section headers
 using the notation: octetString(MAX).  This syntax type is used for
 opaque data.

4.1.11 'boolean'

 The 'boolean' attribute syntax has only two values:  'true' and
 'false'.

4.1.12 'integer'

 The 'integer' attribute syntax is an integer value that is in the
 range from -2**31 (MIN) to 2**31 - 1 (MAX).  Each individual
 attribute may specify the range constraint explicitly in sub-section
 headers if the range is different from the full range of possible
 integer values.  For example:  job-priority (integer(1:100)) for the
 "job-priority" attribute.  However, the enforcement of that
 additional constraint is up to the IPP objects, not the protocol.

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4.1.13 'rangeOfInteger'

 The 'rangeOfInteger' attribute syntax is an ordered pair of integers
 that defines an inclusive range of integer values.  The first integer
 specifies the lower bound and the second specifies the upper bound.
 If a range constraint is specified in the header description for an
 attribute in this document whose attribute syntax is 'rangeOfInteger'
 (i.e., 'X:Y' indicating X as a minimum value and Y as a maximum
 value), then the constraint applies to both integers.

4.1.14 'dateTime'

 The 'dateTime' attribute syntax is a standard, fixed length, 11 octet
 representation of the "DateAndTime" syntax as defined in RFC 2579
 [RFC2579].  RFC 2579 also identifies an 8 octet representation of a
 "DateAndTime" value, but IPP objects MUST use the 11 octet
 representation.  A user interface will provide a mapping between
 protocol dateTime values and displayable user-friendly words or
 presentation values and phrases which are localized to the natural
 language and date format of the user, including time zone.

4.1.15 'resolution'

 The 'resolution' attribute syntax specifies a two-dimensional
 resolution in the indicated units.  It consists of 3 values: a cross
 feed direction resolution (positive integer value), a feed direction
 resolution (positive integer value), and a units value.  The
 semantics of these three components are taken from the Printer MIB
 [RFC1759] suggested values.  That is, the cross feed direction
 component resolution component is the same as the
 prtMarkerAddressabilityXFeedDir object in the Printer MIB, the feed
 direction component resolution component is the same as the
 prtMarkerAddressabilityFeedDir in the Printer MIB, and the units
 component is the same as the prtMarkerAddressabilityUnit object in
 the Printer MIB (namely, '3' indicates dots per inch and '4'
 indicates dots per centimeter).  All three values MUST be present
 even if the first two values are the same.  Example:  '300', '600',
 '3' indicates a 300 dpi cross-feed direction resolution, a 600 dpi
 feed direction resolution, since a '3' indicates dots per inch (dpi).

4.1.16 '1setOf X'

 The '1setOf  X' attribute syntax is 1 or more values of attribute
 syntax type X.  This syntax type is used for multi-valued attributes.
 The syntax type is called '1setOf' rather than just 'setOf' as a
 reminder that the set of values MUST NOT be empty (i.e., a set of

Hastings, et al. Standards Track [Page 90] RFC 2911 IPP/1.1: Model and Semantics September 2000

 size 0).  Sets are normally unordered.  However each attribute
 description of this type may specify that the values MUST be in a
 certain order for that attribute.

4.2 Job Template Attributes

 Job Template attributes describe job processing behavior.  Support
 for Job Template attributes by a Printer object is OPTIONAL (see
 section 12.2.3 for a description of support for OPTIONAL attributes).
 Also, clients OPTIONALLY supply Job Template attributes in create
 requests.
 Job Template attributes conform to the following rules.  For each Job
 Template attribute called "xxx":
    1. If the Printer object supports "xxx" then it MUST support both
       a "xxx-default" attribute (unless there is a "No" in the table
       below) and a "xxx-supported" attribute.  If the Printer object
       doesn't support "xxx", then it MUST support neither an "xxx-
       default" attribute nor an "xxx-supported" attribute, and it
       MUST treat an attribute "xxx" supplied by a client as
       unsupported.  An attribute "xxx" may be supported for some
       document formats and not supported for other document formats.
       For example, it is expected that a Printer object would only
       support "orientation-requested" for some document formats (such
       as 'text/plain' or 'text/html') but not others (such as
       'application/postscript').
    2. "xxx" is OPTIONALLY supplied by the client in a create request.
       If "xxx" is supplied, the client is indicating a desired job
       processing behavior for this Job.  When "xxx" is not supplied,
       the client is indicating that the Printer object apply its
       default job processing behavior at job processing time if the
       document content does not contain an embedded instruction
       indicating an xxx-related behavior.
       Since an administrator MAY change the default value attribute
       after a Job object has been submitted but before it has been
       processed, the default value used by the Printer object at job
       processing time may be different that the default value in
       effect at job submission time.
    3. The "xxx-supported" attribute is a Printer object attribute
       that describes which job processing behaviors are supported by
       that Printer object.  A client can query the Printer object to
       find out what xxx-related behaviors are supported by inspecting
       the returned values of the "xxx-supported" attribute.

Hastings, et al. Standards Track [Page 91] RFC 2911 IPP/1.1: Model and Semantics September 2000

       Note: The "xxx" in each "xxx-supported" attribute name is
       singular, even though an "xxx-supported" attribute usually has
       more than one value, such as "job-sheet-supported", unless the
       "xxx" Job Template attribute is plural, such as "finishings" or
       "sides".  In such cases the "xxx-supported" attribute names
       are: "finishings- supported" and "sides-supported".
    4. The "xxx-default" default value attribute describes what will
       be done at job processing time when no other job processing
       information is supplied by the client (either explicitly as an
       IPP attribute in the create request or implicitly as an
       embedded instruction within the document data).
 If an application wishes to present an end user with a list of
 supported values from which to choose, the application SHOULD query
 the Printer object for its supported value attributes.  The
 application SHOULD also query the default value attributes.  If the
 application then limits selectable values to only those value that
 are supported, the application can guarantee that the values supplied
 by the client in the create request all fall within the set of
 supported values at the Printer.  When querying the Printer, the
 client MAY enumerate each attribute by name in the Get-Printer-
 Attributes Request, or the client MAY just name the "job-template"
 group in order to get the complete set of supported attributes (both
 supported and default attributes).
 The "finishings" attribute is an example of a Job Template attribute.
 It can take on a set of values such as 'staple', 'punch', and/or
 'cover'.  A client can query the Printer object for the "finishings-
 supported" attribute and the "finishings-default" attribute.  The
 supported attribute contains a set of supported values.  The default
 value attribute contains the finishing value(s) that will be used for
 a new Job if the client does not supply a "finishings" attribute in
 the create request and the document data does not contain any
 corresponding finishing instructions.  If the client does supply the
 "finishings" attribute in the create request, the IPP object
 validates the value or values to make sure that they are a subset of
 the supported values identified in the Printer object's "finishings-
 supported" attribute.  See section 3.1.7.
 The table below summarizes the names and relationships for all Job
 Template attributes. The first column of the table (labeled "Job
 Attribute") shows the name and syntax for each Job Template attribute
 in the Job object. These are the attributes that can optionally be
 supplied by the client in a create request.   The last two columns
 (labeled "Printer: Default Value Attribute" and "Printer: Supported
 Values Attribute") show the name and syntax for each Job Template
 attribute in the Printer object (the default value attribute and the

Hastings, et al. Standards Track [Page 92] RFC 2911 IPP/1.1: Model and Semantics September 2000

 supported values attribute).  A "No" in the table means the Printer
 MUST NOT support the attribute (that is, the attribute is simply not
 applicable).  For brevity in the table, the 'text' and 'name' entries
 do not show the maximum length for each attribute.
   +===================+======================+======================+
   | Job Attribute     |Printer: Default Value|  Printer: Supported  |
   |                   |   Attribute          |   Values Attribute   |
   +===================+======================+======================+
   | job-priority      | job-priority-default |job-priority-supported|
   | (integer 1:100)   | (integer 1:100)      |(integer 1:100)       |
   +-------------------+----------------------+----------------------+
   | job-hold-until    | job-hold-until-      |job-hold-until-       |
   | (type3 keyword |  |  default             | supported            |
   |    name)          |  (type3 keyword |    |(1setOf (             |
   |                   |    name)             |type3 keyword | name))|
   +-------------------+----------------------+----------------------+
   | job-sheets        | job-sheets-default   |job-sheets-supported  |
   | (type3 keyword |  | (type3 keyword |     |(1setOf (             |
   |    name)          |    name)             |type3 keyword | name))|
   +-------------------+----------------------+----------------------+
   |multiple-document- |multiple-document-    |multiple-document-    |
   | handling          | handling-default     |handling-supported    |
   | (type2 keyword)   | (type2 keyword)      |(1setOf type2 keyword)|
   +-------------------+----------------------+----------------------+
   | copies            | copies-default       | copies-supported     |
   | (integer (1:MAX)) | (integer (1:MAX))    | (rangeOfInteger      |
   |                   |                      |       (1:MAX))       |
   +-------------------+----------------------+----------------------+
   | finishings        | finishings-default   | finishings-supported |
   |(1setOf type2 enum)|(1setOf type2 enum)   |(1setOf type2 enum)   |
   +-------------------+----------------------+----------------------+
   | page-ranges       | No                   | page-ranges-         |
   | (1setOf           |                      | supported (boolean)  |
   |   rangeOfInteger  |                      |                      |
   |        (1:MAX))   |                      |                      |
   +-------------------+----------------------+----------------------+
   | sides             | sides-default        | sides-supported      |
   | (type2 keyword)   | (type2 keyword)      |(1setOf type2 keyword)|
   +-------------------+----------------------+----------------------+
   | number-up         | number-up-default    | number-up-supported  |
   | (integer (1:MAX)) | (integer (1:MAX))    |(1setOf (integer      |
   |                   |                      | (1:MAX) |            |
   |                   |                      |  rangeOfInteger      |
   |                   |                      |   (1:MAX)))          |

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   +-------------------+----------------------+----------------------+
   | orientation-      |orientation-requested-|orientation-requested-|
   |  requested        |  default             |  supported           |
   |   (type2 enum)    |  (type2 enum)        |  (1setOf type2 enum) |
   +-------------------+----------------------+----------------------+
   | media             | media-default        | media-supported      |
   | (type3 keyword |  | (type3 keyword |     |(1setOf (             |
   |    name)          |    name)             |type3 keyword | name))|
   |                   |                      |                      |
   |                   |                      | media-ready          |
   |                   |                      |(1setOf (             |
   |                   |                      |type3 keyword | name))|
   +-------------------+----------------------+----------------------+
   | printer-resolution| printer-resolution-  | printer-resolution-  |
   | (resolution)      |  default             | supported            |
   |                   | (resolution)         |(1setOf resolution)   |
   +-------------------+----------------------+----------------------+
   | print-quality     | print-quality-default| print-quality-       |
   | (type2 enum)      | (type2 enum)         | supported            |
   |                   |                      |(1setOf type2 enum)   |
   +-------------------+----------------------+----------------------+

4.2.1 job-priority (integer(1:100))

 This attribute specifies a priority for scheduling the Job. A higher
 value specifies a higher priority. The value 1 indicates the lowest
 possible priority. The value 100 indicates the highest possible
 priority.  Among those jobs that are ready to print, a Printer MUST
 print all jobs with a priority value of n before printing those with
 a priority value of n-1 for all n.
 If the Printer object supports this attribute, it MUST always support
 the full range from 1 to 100.  No administrative restrictions are
 permitted.  This way an end-user can always make full use of the
 entire range with any Printer object.  If privileged jobs are
 implemented outside IPP/1.1, they MUST have priorities higher than
 100, rather than restricting the range available to end-users.
 If the client does not supply this attribute and this attribute is
 supported by the Printer object, the Printer object MUST use the
 value of the Printer object's "job-priority-default" at job
 submission time (unlike most Job Template attributes that are used if
 necessary at job processing time).
 The syntax for the "job-priority-supported" is also integer(1:100).
 This single integer value indicates the number of priority levels
 supported.  The Printer object MUST take the value supplied by the
 client and map it to the closest integer in a sequence of n integers

Hastings, et al. Standards Track [Page 94] RFC 2911 IPP/1.1: Model and Semantics September 2000

 values that are evenly distributed over the range from 1 to 100 using
 the formula:
    roundToNearestInt((100x+50)/n)
 where n is the value of "job-priority-supported" and x ranges from 0
 through n-1.
 For example, if n=1 the sequence of values is 50;  if n=2, the
 sequence of values is:  25 and 75;  if n = 3, the sequence of values
 is:  17, 50 and 83;  if n = 10, the sequence of values is: 5, 15, 25,
 35, 45, 55, 65, 75, 85, and 95;  if n = 100, the sequence of values
 is:  1, 2, 3, ... 100.
 If the value of the Printer object's "job-priority-supported" is 10
 and the client supplies values in the range 1 to 10, the Printer
 object maps them to 5, in the range 11 to 20, the Printer object maps
 them to 15, etc.

4.2.2 job-hold-until (type3 keyword | name (MAX))

 This attribute specifies the named time period during which the Job
 MUST become a candidate for printing.
 Standard keyword values for named time periods are:
    'no-hold': immediately, if there are not other reasons to hold the
       job
    'indefinite':  - the job is held indefinitely, until a client
       performs a Release-Job (section 3.3.6)
    'day-time': during the day
    'evening': evening
    'night': night
    'weekend': weekend
    'second-shift': second-shift (after close of business)
    'third-shift': third-shift (after midnight)
 An administrator MUST associate allowable print times with a named
 time period (by means outside the scope of this IPP/1.1 document).
 An administrator is encouraged to pick names that suggest the type of
 time period. An administrator MAY define additional values using the
 'name' or 'keyword' attribute syntax, depending on implementation.
 If the value of this attribute specifies a time period that is in the
 future, the Printer SHOULD add the 'job-hold-until-specified' value
 to the job's "job-state-reasons" attribute, MUST move the job to the

Hastings, et al. Standards Track [Page 95] RFC 2911 IPP/1.1: Model and Semantics September 2000

 'pending-held' state, and MUST NOT schedule the job for printing
 until the specified time-period arrives.
 When the specified time period arrives, the Printer MUST remove the
 'job-hold-until-specified' value from the job's "job-state-reason"
 attribute, if present.  If there are no other job state reasons that
 keep the job in the 'pending-held' state, the Printer MUST consider
 the job as a candidate for processing by moving the job to the
 'pending' state.
 If this job attribute value is the named value 'no-hold', or the
 specified time period has already started, the job MUST be a
 candidate for processing immediately.
 If the client does not supply this attribute and this attribute is
 supported by the Printer object, the Printer object MUST use the
 value of the Printer object's "job-hold-until-default" at job
 submission time (unlike most Job Template attributes that are used if
 necessary at job processing time).

4.2.3 job-sheets (type3 keyword | name(MAX))

 This attribute determines which job start/end sheet(s), if any, MUST
 be printed with a job.
 Standard keyword values are:
    'none': no job sheet is printed
    'standard': one or more site specific standard job sheets are
       printed, e.g. a single start sheet or both start and end sheet is
       printed
 An administrator MAY define additional values using the 'name' or
 'keyword' attribute syntax, depending on implementation.
 The effect of this attribute on jobs with multiple documents MAY be
 affected by the "multiple-document-handling" job attribute (section
 4.2.4), depending on the job sheet semantics.

4.2.4 multiple-document-handling (type2 keyword)

 This attribute is relevant only if a job consists of two or more
 documents. This attribute MUST be supported with at least one value
 if the Printer supports multiple documents per job (see sections
 3.2.4 and 3.3.1).  The attribute controls finishing operations and
 the placement of one or more print-stream pages into impressions and
 onto media sheets.  When the value of the "copies" attribute exceeds
 1, it also controls the order in which the copies that result from

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 processing the documents are produced. For the purposes of this
 explanations, if "a" represents an instance of document data, then
 the result of processing the data in document "a" is a sequence of
 media sheets represented by "a(*)".
 Standard keyword values are:
    'single-document': If a Job object has multiple documents, say,
       the document data is called a and b, then the result of
       processing all the document data (a and then b) MUST be treated
       as a single sequence of media sheets for finishing operations;
       that is, finishing would be performed on the concatenation of
       the sequences a(*),b(*).  The Printer object MUST NOT force the
       data in each document instance to be formatted onto a new
       print-stream page, nor to start a new impression on a new media
       sheet. If more than one copy is made, the ordering of the sets
       of media sheets resulting from processing the document data
       MUST be a(*), b(*), a(*), b(*), start on a new media sheet.
    'separate-documents-uncollated-copies': If a Job object has
       multiple documents, say, the document data is called a and b,
       then the result of processing the data in each document
       instance MUST be treated as a single sequence of media sheets
       for finishing operations; that is, the sets a(*) and b(*) would
       each be finished separately. The Printer object MUST force each
       copy of the result of processing the data in a single document
       to start on a new media sheet. If more than one copy is made,
       the ordering of the sets of media sheets resulting from
       processing the document data MUST be a(*), a(*), ..., b(*),
       b(*) ... .
    'separate-documents-collated-copies': If a Job object has multiple
       documents, say, the document data is called a and b, then the
       result of processing the data in each document instance MUST be
       treated as a single sequence of media sheets for finishing
       operations; that is, the sets a(*) and b(*) would each be
       finished separately. The Printer object MUST force each copy of
       the result of processing the data in a single document to start
       on a new media sheet.  If more than one copy is made, the
       ordering of the sets of media sheets resulting from processing
       the document data MUST be a(*), b(*), a(*), b(*), ... .
    'single-document-new-sheet':  Same as 'single-document', except
       that the Printer object MUST ensure that the first impression
       of each document instance in the job is placed on a new media
       sheet.  This value allows multiple documents to be stapled
       together with a single staple where each document starts on a
       new sheet.

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 The 'single-document' value is the same as 'separate-documents-
 collated-copies' with respect to ordering of print-stream pages, but
 not media sheet generation, since 'single-document' will put the
 first page of the next document on the back side of a sheet if an odd
 number of pages have been produced so far for the job, while
 'separate-documents-collated- copies' always forces the next document
 or document copy on to a new sheet.  In addition, if the "finishings"
 attribute specifies 'staple', then with 'single-document', documents
 a and b are stapled together as a single document with no regard to
 new sheets, with 'single-document-new-sheet', documents a and b are
 stapled together as a single document, but document b starts on a new
 sheet, but with 'separate-documents-uncollated-copies' and
 'separate-documents-collated-copies', documents a and b are stapled
 separately.
 Note: None of these values provide means to produce uncollated sheets
 within a document, i.e., where multiple copies of sheet n are
 produced before sheet n+1 of the same document.
 The relationship of this attribute and the other attributes that
 control document processing is described in section 15.3.

4.2.5 copies (integer(1:MAX))

 This attribute specifies the number of copies to be printed.
 On many devices the supported number of collated copies will be
 limited by the number of physical output bins on the device, and may
 be different from the number of uncollated copies which can be
 supported.
 Note: The effect of this attribute on jobs with multiple documents is
 controlled by the "multiple-document-handling" job attribute (section
 4.2.4) and the relationship of this attribute and the other
 attributes that control document processing is described in section
 15.3.

4.2.6 finishings (1setOf type2 enum)

 This attribute identifies the finishing operations that the Printer
 uses for each copy of each printed document in the Job. For Jobs with
 multiple documents, the "multiple-document-handling" attribute
 determines what constitutes a "copy" for purposes of finishing.

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 Standard enum values are:
 Value  Symbolic Name and Description
 '3'    'none':  Perform no finishing
 '4'    'staple':  Bind the document(s) with one or more staples. The
           exact number and placement of the staples is site-
           defined.
 '5'    'punch':  This value indicates that holes are required in the
           finished document. The exact number and placement of the
           holes is site-defined  The punch specification MAY be
           satisfied (in a site- and implementation-specific manner)
           either by drilling/punching, or by substituting pre-
           drilled media.
 '6'    'cover':  This value is specified when it is desired to select
           a non-printed (or pre-printed) cover for the document.
           This does not supplant the specification of a printed
           cover (on cover stock medium) by the document itself.
 '7'    'bind':  This value indicates that a binding is to be applied
           to the document; the type and placement of the binding is
           site-defined.
 '8'    'saddle-stitch':  Bind the document(s) with one or more
           staples (wire stitches) along the middle fold.  The exact
           number and placement of the staples and the middle fold
           is implementation and/or site-defined.
 '9'    'edge-stitch':  Bind the document(s) with one or more staples
           (wire stitches) along one edge.  The exact number and
           placement of the staples is implementation and/or site-
           defined.
 '10'-'19'   reserved for future generic finishing enum values.
 The following values are more specific; they indicate a corner or an
 edge as if the document were a portrait document (see below):
 '20'   'staple-top-left':  Bind the document(s) with one or more
           staples in the top left corner.
 '21'   'staple-bottom-left':  Bind the document(s) with one or more
           staples in the bottom left corner.
 '22'   'staple-top-right':  Bind the document(s) with one or more
           staples in the top right corner.
 '23'   'staple-bottom-right':  Bind the document(s) with one or more
           staples in the bottom right corner.
 '24'   'edge-stitch-left':  Bind the document(s) with one or more
           staples (wire stitches) along the left edge.  The exact
           number and placement of the staples is implementation
           and/or site-defined.

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 '25'   'edge-stitch-top':  Bind the document(s) with one or more
           staples (wire stitches) along the top edge.  The exact
           number and placement of the staples is implementation
           and/or site-defined.
 '26'   'edge-stitch-right':  Bind the document(s) with one or more
           staples (wire stitches) along the right edge.  The exact
           number and placement of the staples is implementation
           and/or site-defined.
 '27'   'edge-stitch-bottom':  Bind the document(s) with one or more
           staples (wire stitches) along the bottom edge.  The exact
           number and placement of the staples is implementation
           and/or site-defined.
 '28'   'staple-dual-left':  Bind the document(s) with two staples
           (wire stitches) along the left edge assuming a portrait
           document (see above).
 '29'   'staple-dual-top':  Bind the document(s) with two staples
           (wire stitches) along the top edge assuming a portrait
           document (see above).
 '30'   'staple-dual-right':  Bind the document(s) with two staples
           (wire stitches) along the right edge assuming a portrait
           document (see above).
 '31'   'staple-dual-bottom':  Bind the document(s) with two staples
           (wire stitches) along the bottom edge assuming a portrait
           document (see above).
 The 'staple-xxx' values are specified with respect to the document as
 if the document were a portrait document.  If the document is
 actually a landscape or a reverse-landscape document, the client
 supplies the appropriate transformed value.  For example, to position
 a staple in the upper left hand corner of a landscape document when
 held for reading, the client supplies the 'staple-bottom-left' value
 (since landscape is defined as a +90 degree rotation of the image
 with respect to the media from portrait, i.e., anti-clockwise).  On
 the other hand, to position a staple in the upper left hand corner of
 a reverse-landscape document when held for reading, the client
 supplies the 'staple-top-right' value (since reverse-landscape is
 defined as a -90 degree rotation of the image with respect to the
 media from portrait, i.e., clockwise).
 The angle (vertical, horizontal, angled) of each staple with respect
 to the document depends on the implementation which may in turn
 depend on the value of the attribute.
 Note: The effect of this attribute on jobs with multiple documents is
 controlled by the "multiple-document-handling" job attribute (section
 4.2.4) and the relationship of this attribute and the other
 attributes that control document processing is described in section
 15.3.

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 If the client supplies a value of 'none' along with any other
 combination of values, it is the same as if only that other
 combination of values had been supplied (that is the 'none' value has
 no effect).

4.2.7 page-ranges (1setOf rangeOfInteger (1:MAX))

 This attribute identifies the range(s) of print-stream pages that the
 Printer object uses for each copy of each document which are to be
 printed.  Nothing is printed for any pages identified that do not
 exist in the document(s).  Ranges MUST be in ascending order, for
 example: 1-3, 5-7, 15-19 and MUST NOT overlap, so that a non-spooling
 Printer object can process the job in a single pass.  If the ranges
 are not ascending or are overlapping, the IPP object MUST reject the
 request and return the 'client-error-bad-request' status code.  The
 attribute is associated with print-stream pages not application-
 numbered pages (for example, the page numbers found in the headers
 and or footers for certain word processing applications).
 For Jobs with multiple documents, the "multiple-document-handling"
 attribute determines what constitutes a "copy" for purposes of the
 specified page range(s).  When "multiple-document-handling" is
 'single-document', the Printer object MUST apply each supplied page
 range once to the concatenation of the print-stream pages.  For
 example, if there are 8 documents of 10 pages each, the page-range
 '41:60' prints the pages in the 5th and 6th documents as a single
 document and none of the pages of the other documents are printed.
 When "multiple-document- handling" is 'separate-documents-
 uncollated-copies' or 'separate-documents-collated-copies', the
 Printer object MUST apply each supplied page range repeatedly to each
 document copy.  For the same job, the page-range '1:3, 10:10' would
 print the first 3 pages and the 10th page of each of the 8 documents
 in the Job, as 8 separate documents.
 In most cases, the exact pages to be printed will be generated by a
 device driver and this attribute would not be required.  However,
 when printing an archived document which has already been formatted,
 the end user may elect to print just a subset of the pages contained
 in the document.  In this case, if page-range = n.m is specified, the
 first page to be printed will be page n. All subsequent pages of the
 document will be printed through and including page m.
 "page-ranges-supported" is a boolean value indicating whether or not
 the printer is capable of supporting the printing of page ranges.
 This capability may differ from one PDL to another. There is no
 "page-ranges-default" attribute.  If the "page-ranges" attribute is
 not supplied by the client, all pages of the document will be
 printed.

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 Note: The effect of this attribute on jobs with multiple documents is
 controlled by the "multiple-document-handling" job attribute (section
 4.2.4) and the relationship of this attribute and the other
 attributes that control document processing is described in section
 15.3.

4.2.8 sides (type2 keyword)

 This attribute specifies how print-stream pages are to be imposed
 upon the sides of an instance of a selected medium, i.e., an
 impression.
 The standard keyword values are:
    'one-sided': imposes each consecutive print-stream page upon the
       same side of consecutive media sheets.
    'two-sided-long-edge': imposes each consecutive pair of print-
       stream pages upon front and back sides of consecutive media
       sheets, such that the orientation of each pair of print-stream
       pages on the medium would be correct for the reader as if for
       binding on the long edge.  This imposition is sometimes called
       'duplex' or 'head-to-head'.
    'two-sided-short-edge': imposes each consecutive pair of print-
       stream pages upon front and back sides of consecutive media
       sheets, such that the orientation of each pair of print-stream
       pages on the medium would be correct for the reader as if for
       binding on the short edge.  This imposition is sometimes called
       'tumble' or 'head-to-toe'.
    'two-sided-long-edge', 'two-sided-short-edge',
       'tumble', and 'duplex' all work the same for portrait or
       landscape.  However
       'head-to-toe' is
    'tumble' in portrait but 'duplex' in landscape.  'head-to-head'
       also switches between 'duplex' and 'tumble' when using portrait
       and landscape modes.
 Note: The effect of this attribute on jobs with multiple documents is
 controlled by the "multiple-document-handling" job attribute (section
 4.2.4) and the relationship of this attribute and the other
 attributes that control document processing is described in section
 15.3.

4.2.9 number-up (integer(1:MAX))

 This attribute specifies the number of print-stream pages to impose
 upon a single side of an instance of a selected medium.  For example,
 if the value is:

Hastings, et al. Standards Track [Page 102] RFC 2911 IPP/1.1: Model and Semantics September 2000

 Value  Description
 '1'    the Printer MUST place one print-stream page on a single side
           of an instance of the selected medium (MAY add some sort
           of translation, scaling, or rotation).
 '2'    the Printer MUST place two print-stream pages on a single side
           of an instance of the selected medium (MAY add some sort
           of translation, scaling, or rotation).
 '4'    the Printer MUST place four print-stream pages on a single
           side of an instance of the selected medium (MAY add some
           sort of translation, scaling, or rotation).
 This attribute primarily controls the translation, scaling and
 rotation of print-stream pages.
 Note: The effect of this attribute on jobs with multiple documents is
 controlled by the "multiple-document-handling" job attribute (section
 4.2.4) and the relationship of this attribute and the other
 attributes that control document processing is described in section
 15.3.

4.2.10 orientation-requested (type2 enum)

 This attribute indicates the desired orientation for printed print-
 stream pages; it does not describe the orientation of the client-
 supplied print-stream pages.
 For some document formats (such as 'application/postscript'), the
 desired orientation of the print-stream pages is specified within the
 document data.  This information is generated by a device driver
 prior to the submission of the print job.  Other document formats
 (such as 'text/plain') do not include the notion of desired
 orientation within the document data.  In the latter case it is
 possible for the Printer object to bind the desired orientation to
 the document data after it has been submitted.  It is expected that a
 Printer object would only support "orientations-requested" for some
 document formats (e.g., 'text/plain' or 'text/html') but not others
 (e.g., 'application/postscript').  This is no different than any
 other Job Template attribute since section 4.2, item 1, points out
 that a Printer object may support or not support any Job Template
 attribute based on the document format supplied by the client.
 However, a special mention is made here since it is very likely that
 a Printer object will support "orientation-requested" for only a
 subset of the supported document formats.

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 Standard enum values are:
 Value  Symbolic Name and Description
 '3'    'portrait':  The content will be imaged across the short edge
           of the medium.
 '4'    'landscape':  The content will be imaged across the long edge
           of the medium.  Landscape is defined to be a rotation of
           the print-stream page to be imaged by +90 degrees with
           respect to the medium (i.e. anti-clockwise) from the
           portrait orientation.  Note:  The +90 direction was
           chosen because simple finishing on the long edge is the
           same edge whether portrait or landscape
 '5'    'reverse-landscape':  The content will be imaged across the
           long edge of the medium.  Reverse-landscape is defined to
           be a rotation of the print-stream page to be imaged by -
           90 degrees with respect to the medium (i.e. clockwise)
           from the portrait orientation.  Note: The 'reverse-
           landscape' value was added because some applications
           rotate landscape -90 degrees from portrait, rather than
           +90 degrees.
 '6'    'reverse-portrait':  The content will be imaged across the
           short edge of the medium.  Reverse-portrait is defined to
           be a rotation of the print-stream page to be imaged by
           180 degrees with respect to the medium from the portrait
           orientation.  Note: The 'reverse-portrait' value was
           added for use with the "finishings" attribute in cases
           where the opposite edge is desired for finishing a
           portrait document on simple finishing devices that have
           only one finishing position.  Thus a 'text'/plain'
           portrait document can be stapled "on the right" by a
           simple finishing device as is common use with some middle
           eastern languages such as Hebrew.
 Note: The effect of this attribute on jobs with multiple documents is
 controlled by the "multiple-document-handling" job attribute (section
 4.2.4) and the relationship of this attribute and the other
 attributes that control document processing is described in section
 15.3.

4.2.11 media (type3 keyword | name(MAX))

 This attribute identifies the medium that the Printer uses for all
 impressions of the Job.
 The values for "media" include medium-names, medium-sizes, input-
 trays and electronic forms so that one attribute specifies the media.
 If a Printer object supports a medium name as a value of this

Hastings, et al. Standards Track [Page 104] RFC 2911 IPP/1.1: Model and Semantics September 2000

 attribute, such a medium name implicitly selects an input-tray that
 contains the specified medium.  If a Printer object supports a medium
 size as a value of this attribute, such a medium size implicitly
 selects a medium name that in turn implicitly selects an input-tray
 that contains the medium with the specified size.  If a Printer
 object supports an input-tray as the value of this attribute, such an
 input-tray implicitly selects the medium that is in that input-tray
 at the time the job prints.  This case includes manual-feed input-
 trays.  If a Printer object supports an electronic form as the value
 of this attribute, such an electronic form implicitly selects a
 medium-name that in turn implicitly selects an input-tray that
 contains the medium specified by the electronic form.  The electronic
 form also implicitly selects an image that the Printer MUST merge
 with the document data as its prints each page.
 Standard keyword values are taken from ISO DPA [ISO10175], the
 Printer MIB [RFC1759], and ASME-Y14.1M [ASME-Y14.1M] and are listed
 in section 14.  An administrator MAY define additional values using
 the 'name' or 'keyword' attribute syntax, depending on
 implementation.
 There is also an additional Printer attribute named "media-ready"
 which differs from "media-supported" in that legal values only
 include the subset of "media-supported" values that are physically
 loaded and ready for printing with no operator intervention required.
 If an IPP object supports "media-supported", it NEED NOT support
 "media-ready".
 The relationship of this attribute and the other attributes that
 control document processing is described in section 15.3.

4.2.12 printer-resolution (resolution)

 This attribute identifies the resolution that Printer uses for the
 Job.

4.2.13 print-quality (type2 enum)

 This attribute specifies the print quality that the Printer uses for
 the Job.
 The standard enum values are:
 Value  Symbolic Name and Description
 '3'    'draft': lowest quality available on the printer
 '4'    'normal': normal or intermediate quality on the printer
 '5'    'high': highest quality available on the printer

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4.3 Job Description Attributes

 The attributes in this section form the attribute group called "job-
 description".  The following table summarizes these attributes.  The
 third column indicates whether the attribute is a REQUIRED attribute
 that MUST be supported by Printer objects.  If it is not indicated as
 REQUIRED, then it is OPTIONAL.  The maximum size in octets for 'text'
 and 'name' attributes is indicated in parenthesizes.
 +----------------------------+----------------------+--------------+
 |      Attribute             |     Syntax           |   REQUIRED?  |
 +----------------------------+----------------------+--------------+
 | job-uri                    | uri                  |  REQUIRED    |
 +----------------------------+----------------------+--------------+
 | job-id                     | integer(1:MAX)       |  REQUIRED    |
 +----------------------------+----------------------+--------------+
 | job-printer-uri            | uri                  |  REQUIRED    |
 +----------------------------+----------------------+--------------+
 | job-more-info              | uri                  |              |
 +----------------------------+----------------------+--------------+
 | job-name                   | name (MAX)           |  REQUIRED    |
 +----------------------------+----------------------+--------------+
 | job-originating-user-name  | name (MAX)           |  REQUIRED    |
 +----------------------------+----------------------+--------------+
 | job-state                  | type1 enum           |  REQUIRED    |
 +----------------------------+----------------------+--------------+
 | job-state-reasons          | 1setOf type2 keyword |  REQUIRED    |
 +----------------------------+----------------------+--------------+
 | job-state-message          | text (MAX)           |              |
 +----------------------------+----------------------+--------------+
 | job-detailed-status-       | 1setOf text (MAX)    |              |
 |       messages             |                      |              |
 +----------------------------+----------------------+--------------+
 | job-document-access-errors | 1setOf text (MAX)    |              |
 +----------------------------+----------------------+--------------+
 | number-of-documents        | integer (0:MAX)      |              |
 +----------------------------+----------------------+--------------+
 | output-device-assigned     | name (127)           |              |
 +----------------------------+----------------------+--------------+
 | time-at-creation           | integer (MIN:MAX)    |  REQUIRED    |
 +----------------------------+----------------------+--------------+
 | time-at-processing         | integer (MIN:MAX)    |  REQUIRED    |
 +----------------------------+----------------------+--------------+
 | time-at-completed          | integer (MIN:MAX)    |  REQUIRED    |
 +----------------------------+----------------------+--------------+
 | job-printer-up-time        | integer (1:MAX)      |  REQUIRED    |
 +----------------------------+----------------------+--------------+
 | date-time-at-creation      | dateTime             |              |

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 +----------------------------+----------------------+--------------+
 | date-time-at-processing    | dateTime             |              |
 +----------------------------+----------------------+--------------+
 | date-time-at-completed     | dateTime             |              |
 +----------------------------+----------------------+--------------+
 | number-of-intervening-jobs | integer (0:MAX)      |              |
 +----------------------------+----------------------+--------------+
 | job-message-from-operator  | text (127)           |              |
 +----------------------------+----------------------+--------------+
 | job-k-octets               | integer (0:MAX)      |              |
 +----------------------------+----------------------+--------------+
 | job-impressions            | integer (0:MAX)      |              |
 +----------------------------+----------------------+--------------+
 | job-media-sheets           | integer (0:MAX)      |              |
 +----------------------------+----------------------+--------------+
 | job-k-octets-processed     | integer (0:MAX)      |              |
 +----------------------------+----------------------+--------------+
 | job-impressions-completed  | integer (0:MAX)      |              |
 +----------------------------+----------------------+--------------+
 | job-media-sheets-completed | integer (0:MAX)      |              |
 +----------------------------+----------------------+--------------+
 | attributes-charset         | charset              |  REQUIRED    |
 +----------------------------+----------------------+--------------+
 | attributes-natural-language| naturalLanguage      |  REQUIRED    |
 +----------------------------+----------------------+--------------+

4.3.1 job-uri (uri)

 This REQUIRED attribute contains the URI for the job.  The Printer
 object, on receipt of a new job, generates a URI which identifies the
 new Job.  The Printer object returns the value of the "job-uri"
 attribute as part of the response to a create request.  The precise
 format of a Job URI is implementation dependent.  If the Printer
 object supports more than one URI and there is some relationship
 between the newly formed Job URI and the Printer object's URI, the
 Printer object uses the Printer URI supplied by the client in the
 create request.  For example, if the create request comes in over a
 secure channel, the new Job URI MUST use the same secure channel.
 This can be guaranteed because the Printer object is responsible for
 generating the Job URI and the Printer object is aware of its
 security configuration and policy as well as the Printer URI used in
 the create request.
 For a description of this attribute and its relationship to "job-id"
 and "job-printer-uri" attribute, see the discussion in section 2.4 on
 "Object Identity".

Hastings, et al. Standards Track [Page 107] RFC 2911 IPP/1.1: Model and Semantics September 2000

4.3.2 job-id (integer(1:MAX))

 This REQUIRED attribute contains the ID of the job.  The Printer, on
 receipt of a new job, generates an ID which identifies the new Job on
 that Printer.  The Printer returns the value of the "job-id"
 attribute as part of the response to a create request.  The 0 value
 is not included to allow for compatibility with SNMP index values
 which also cannot be 0.
 For a description of this attribute and its relationship to "job-uri"
 and "job-printer-uri" attribute, see the discussion in section 2.4 on
 "Object Identity".

4.3.3 job-printer-uri (uri)

 This REQUIRED attribute identifies the Printer object that created
 this Job object.  When a Printer object creates a Job object, it
 populates this attribute with the Printer object URI that was used in
 the create request.  This attribute permits a client to identify the
 Printer object that created this Job object when only the Job
 object's URI is available to the client.  The client queries the
 creating Printer object to determine which languages, charsets,
 operations, are supported for this Job.
 For a description of this attribute and its relationship to "job-uri"
 and "job-id" attribute, see the discussion in section 2.4 on "Object
 Identity".

4.3.4 job-more-info (uri)

 Similar to "printer-more-info", this attribute contains the URI
 referencing some resource with more information about this Job
 object, perhaps an HTML page containing information about the Job.

4.3.5 job-name (name(MAX))

 This REQUIRED attribute is the name of the job.  It is a name that is
 more user friendly than the "job-uri" attribute value.  It does not
 need to be unique between Jobs.  The Job's "job-name" attribute is
 set to the value supplied by the client in the "job-name" operation
 attribute in the create request (see Section 3.2.1.1).   If, however,
 the "job-name" operation attribute is not supplied by the client in
 the create request, the Printer object, on creation of the Job, MUST
 generate a name.  The printer SHOULD generate the value of the Job's
 "job-name" attribute from the first of the following sources that
 produces a value: 1) the "document-name" operation attribute of the

Hastings, et al. Standards Track [Page 108] RFC 2911 IPP/1.1: Model and Semantics September 2000

 first (or only) document, 2) the "document-URI" attribute of the
 first (or only) document, or 3) any other piece of Job specific
 and/or Document Content information.

4.3.6 job-originating-user-name (name(MAX))

 This REQUIRED attribute contains the name of the end user that
 submitted the print job.  The Printer object sets this attribute to
 the most authenticated printable name that it can obtain from the
 authentication service over which the IPP operation was received.
 Only if such is not available, does the Printer object use the value
 supplied by the client in the "requesting-user-name" operation
 attribute of the create operation (see Sections 4.4.2, 4.4.3, and 8).
 Note:  The Printer object needs to keep an internal originating user
 id of some form, typically as a credential of a principal, with the
 Job object.  Since such an internal attribute is implementation-
 dependent and not of interest to clients, it is not specified as a
 Job Description attribute.  This originating user id is used for
 authorization checks (if any) on all subsequent operations.

4.3.7 job-state (type1 enum)

 This REQUIRED attribute identifies the current state of the job.
 Even though the IPP protocol defines seven values for job states
 (plus the out-of-band 'unknown' value - see Section 4.1),
 implementations only need to support those states which are
 appropriate for the particular implementation.  In other words, a
 Printer supports only those job states implemented by the output
 device and available to the Printer object implementation.
 Standard enum values are:
 Values Symbolic Name and Description
 '3'  'pending':  The job is a candidate to start processing, but is
         not yet processing.
 '4'  'pending-held':  The job is not a candidate for processing for
         any number of reasons but will return to the 'pending'
         state as soon as the reasons are no longer present.  The
         job's "job-state-reason" attribute MUST indicate why the
         job is no longer a candidate for processing.

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 '5'  'processing':  One or more of:
         1.  the job is using, or is attempting to use, one or
         more purely software processes that are analyzing,
         creating, or interpreting a PDL, etc.,
         2.  the job is using, or is attempting to use, one or
         more hardware devices that are interpreting a PDL, making
         marks on a medium, and/or performing finishing, such as
         stapling, etc.,
         3. the Printer object has made the job ready for
         printing, but the output device is not yet printing it,
         either because the job hasn't reached the output device
         or because the job is queued in the output device or some
         other spooler, awaiting the output device to print it.
         When the job is in the 'processing' state, the entire job
         state includes the detailed status represented in the
         Printer object's "printer-state", "printer-state-
         reasons", and "printer-state-message" attributes.
         Implementations MAY, though they NEED NOT,  include
         additional values in the job's "job-state-reasons"
         attribute to indicate the progress of the job, such as
         adding the 'job-printing' value to indicate when the
         output device is actually making marks on paper and/or
         the 'processing-to-stop-point' value to indicate that the
         IPP object is in the process of canceling or aborting the
         job.  Most implementations won't bother with this nuance.
 '6'  'processing-stopped':  The job has stopped while processing
         for any number of reasons and will return to the
         'processing' state as soon as the reasons are no longer
         present.
         The job's "job-state-reason" attribute MAY indicate why
         the job has stopped processing.  For example, if the
         output device is stopped, the 'printer-stopped' value MAY
         be included in the job's "job-state-reasons" attribute.
         Note:  When an output device is stopped, the device
         usually indicates its condition in human readable form
         locally at the device.  A client can obtain more complete
         device status remotely by querying the Printer object's
         "printer-state", "printer-state-reasons" and "printer-
         state-message" attributes.
 '7'  'canceled':  The job has been canceled by a Cancel-Job
         operation and the Printer object has completed canceling

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         the job and all job status attributes have reached their
         final values for the job.  While the Printer object is
         canceling the job, the job remains in its current state,
         but the job's "job-state-reasons" attribute SHOULD
         contain the 'processing-to-stop-point' value and one of
         the 'canceled-by-user', 'canceled-by-operator', or
         'canceled-at-device' value.  When the job moves to the
         'canceled' state, the  'processing-to-stop-point' value,
         if present, MUST be removed, but the 'canceled-by-xxx',
         if present, MUST remain.
 '8'  'aborted':  The job has been aborted by the system, usually
         while the job was in the 'processing' or 'processing-
         stopped' state and the Printer has completed aborting the
         job and all job status attributes have reached their
         final values for the job.  While the Printer object is
         aborting the job, the job remains in its current state,
         but the job's "job-state-reasons" attribute SHOULD
         contain the 'processing-to-stop-point' and 'aborted-by-
         system' values.  When the job moves to the 'aborted'
         state, the  'processing-to-stop-point' value, if present,
         MUST be removed, but the 'aborted-by-system' value, if
         present, MUST remain.
 '9'  'completed':  The job has completed successfully or with
         warnings or errors after processing and all of the job
         media sheets have been successfully stacked in the
         appropriate output bin(s) and all job status attributes
         have reached their final values for the job.  The job's
         "job-state-reasons" attribute SHOULD contain one of:
         'completed-successfully', 'completed-with-warnings', or
         'completed-with-errors' values.
 The final value for this attribute MUST be one of: 'completed',
 'canceled', or 'aborted' before the Printer removes the job
 altogether.  The length of time that jobs remain in the 'canceled',
 'aborted', and 'completed' states depends on implementation.  See
 section 4.3.7.2.
 The following figure shows the normal job state transitions.
                                                    +----> canceled
                                                   /
     +----> pending --------> processing ---------+------> completed
     |         ^                   ^               \
 --->+         |                   |                +----> aborted
     |         v                   v               /
     +----> pending-held    processing-stopped ---+

Hastings, et al. Standards Track [Page 111] RFC 2911 IPP/1.1: Model and Semantics September 2000

 Normally a job progresses from left to right.  Other state
 transitions are unlikely, but are not forbidden.  Not shown are the
 transitions to the 'canceled' state from the 'pending', 'pending-
 held', and 'processing-stopped' states.
 Jobs reach one of the three terminal states: 'completed', 'canceled',
 or 'aborted', after the jobs have completed all activity, including
 stacking output media, after the jobs have completed all activity,
 and all job status attributes have reached their final values for the
 job.

4.3.7.1 Forwarding Servers

 As with all other IPP attributes, if the implementation cannot
 determine the correct value for this attribute, it SHOULD respond
 with the out-of-band value 'unknown' (see section 4.1) rather than
 try to guess at some possibly incorrect value and give the end user
 the wrong impression about the state of the Job object.  For example,
 if the implementation is just a gateway into some printing system
 from which it can normally get status, but temporarily is unable,
 then the implementation should return the 'unknown' value.  However,
 if the implementation is a gateway to a printing system that never
 provides detailed status about the print job, the implementation MAY
 set the IPP Job object's state  to 'completed', provided that it also
 sets the 'queued-in-device' value in the job's "job-state-reasons"
 attribute (see section 4.3.8).

4.3.7.2 Partitioning of Job States

 This section partitions the 7 job states into phases:  Job Not
 Completed, Job Retention, Job History, and Job Removal.  This section
 also explains the 'job-restartable' value of the "job-state-reasons"
 Job Description attribute for use with the Restart-Job operation.
 Job Not Completed:  When a job is in the 'pending', 'pending-held',
 'processing', or 'processing-stopped' states, the job is not
 completed.
 Job Retention:  When a job enters one of the three terminal job
 states:  'completed', 'canceled', or 'aborted', the IPP Printer
 object MAY "retain" the job in a restartable condition for an
 implementation-defined time period.  This time period MAY be zero
 seconds and MAY depend on the terminal job state.  This phase is
 called Job Retention.  While in the Job Retention phase, the job's
 document data is retained and a client may restart the job using the
 Restart-Job operation.  If the IPP object supports the Restart-Job

Hastings, et al. Standards Track [Page 112] RFC 2911 IPP/1.1: Model and Semantics September 2000

 operation, then it SHOULD indicate that the job is restartable by
 adding the 'job-restartable' value to the job's "job-state-reasons"
 attribute (see Section 4.3.8) during the Job Retention phase.
 Job History:  After the Job Retention phase expires for a job, the
 Printer object deletes the document data for the job and the job
 becomes part of the Job History.  The Printer object MAY also delete
 any number of the job attributes.  Since the job is no longer
 restartable, the Printer object MUST remove the 'job-restartable'
 value from the job's "job-state-reasons" attribute, if present.
 Job Removal:  After the job has remained in the Job History for an
 implementation-defined time, such as when the number of jobs exceeds
 a fixed number or after a fixed time period (which MAY be zero
 seconds), the IPP Printer removes the job from the system.
 Using the Get-Jobs operation and supplying the 'not-completed' value
 for the "which-jobs" operation attribute, a client is requesting jobs
 in the Job Not Completed phase.  Using the Get-Jobs operation and
 supplying the 'completed' value for the "which-jobs" operation
 attribute, a client is requesting jobs in the Job Retention and Job
 History phases.  Using the Get-Job-Attributes operation, a client is
 requesting a job in any phase except Job Removal.  After Job Removal,
 the Get-Job-Attributes and Get-Jobs operations no longer are capable
 of returning any information about a job.

4.3.8 job-state-reasons (1setOf type2 keyword)

 This REQUIRED attribute provides additional information about the
 job's current state, i.e., information that augments the value of the
 job's "job-state" attribute.
 These values MAY be used with any job state or states for which the
 reason makes sense.  Some of these value definitions indicate
 conformance requirements; the rest are OPTIONAL.  Furthermore, when
 implemented, the Printer MUST return these values when the reason
 applies and MUST NOT return them when the reason no longer applies
 whether the value of the Job's "job-state" attribute changed or not.
 When the Job does not have any reasons for being in its current
 state, the value of the Job's "job-state-reasons" attribute MUST be
 'none'.
 Note: While values cannot be added to the 'job-state' attribute
 without impacting deployed clients that take actions upon receiving
 "job-state" values, it is the intent that additional "job-state-
 reasons" values can be defined and registered without impacting such
 deployed clients.  In other words, the "job-state-reasons" attribute
 is intended to be extensible.

Hastings, et al. Standards Track [Page 113] RFC 2911 IPP/1.1: Model and Semantics September 2000

 The following standard keyword values are defined.  For ease of
 understanding, the values are presented in the order in which the
 reasons are likely to occur (if implemented), starting with the
 'job-incoming' value:
    'none':  There are no reasons for the job's current state.  This
       state reason is semantically equivalent to "job-state-reasons"
       without any value and MUST be used when there is no other
       value, since the 1setOf attribute syntax requires at least one
       value.
    'job-incoming':  Either (1) the Printer has accepted the Create-
       Job operation and is expecting additional Send-Document and/or
       Send-URI operations, or (2) the Printer is retrieving/accepting
       document data as a result of a Print-Job, Print-URI, Send-
       Document or Send-URI operation.
    'job-data-insufficient':  The Create-Job operation has been
       accepted by the Printer, but the Printer is expecting
       additional document data before it can move the job into the
       'processing' state.  If a Printer starts processing before it
       has received all data, the Printer removes the 'job-data-
       insufficient' reason, but the 'job-incoming' remains.  If a
       Printer starts processing after it has received all data, the
       Printer removes the 'job-data-insufficient' reason and the
       'job-incoming' at the same time.
    'document-access-error':  After accepting a Print-URI or Send-URI
       request, the Printer could not access one or more documents
       passed by reference.  This reason is intended to cover any file
       access problem, including file does not exist and access denied
       because of an access control problem.  The Printer MAY also
       indicate the document access error using the "job-document-
       access-errors" Job Description attribute (see section 4.3.11).
       Whether the Printer aborts the job and moves the job to the
       'aborted' job state or prints all documents that are accessible
       and moves the job to the 'completed' job state and adds the
       'completed-with-errors' value in the job's "job-state-reasons"
       attribute depends on implementation and/or site policy.  This
       value SHOULD be supported if the Print-URI or Send-URI
       operations are supported.
    'submission-interrupted':  The job was not completely submitted
       for some unforeseen reason, such as: (1) the Printer has
       crashed before the job was closed by the client, (2) the
       Printer or the document transfer method has crashed in some
       non-recoverable way before the document data was entirely
       transferred to the Printer, (3) the client crashed or failed to
       close the job before the time-out period.  See section 4.4.31.
    'job-outgoing':  The Printer is transmitting the job to the output
       device.

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    'job-hold-until-specified':  The value of the job's "job-hold-
       until" attribute was specified with a time period that is still
       in the future.  The job MUST NOT be a candidate for processing
       until this reason is removed and there are no other reasons to
       hold the job.  This value SHOULD be supported if the "job-
       hold-until" Job Template attribute is supported.
    'resources-are-not-ready':  At least one of the resources needed
       by the job, such as media, fonts, resource objects, etc., is
       not ready on any of the physical printer's for which the job is
       a candidate.  This condition MAY be detected when the job is
       accepted, or subsequently while the job is pending or
       processing, depending on implementation.  The job may remain in
       its current state or be moved to the 'pending-held' state,
       depending on implementation and/or job scheduling policy.
    'printer-stopped-partly':  The value of the Printer's "printer-
       state-reasons" attribute contains the value 'stopped-partly'.
    'printer-stopped':  The value of the Printer's "printer-state"
       attribute is 'stopped'.
    'job-interpreting': Job is in the 'processing' state, but more
       specifically, the Printer is interpreting the document data.
    'job-queued': Job is in the 'processing' state, but more
       specifically, the Printer has queued the document data.
    'job-transforming': Job is in the 'processing' state, but more
       specifically, the Printer is interpreting document data and
       producing another electronic representation.
    'job-queued-for-marker': Job is in any of the 'pending-held',
       'pending', or 'processing' states, but more specifically, the
       Printer has completed enough processing of the document to be
       able to start marking and the job is waiting for the marker.
       Systems that require human intervention to release jobs using
       the Release-Job operation, put the job into the 'pending-held'
       job state.  Systems that automatically select a job to use the
       marker put the job into the  'pending' job state or keep the
       job in the 'processing' job state while waiting for the marker,
       depending on implementation.  All implementations put the job
       into (or back into) the 'processing' state when marking does
       begin.
    'job-printing':  The output device is marking media. This value is
       useful for Printers which spend a great deal of time processing
       (1) when no marking is happening and then want to show that
       marking is now happening or (2) when the job is in the process
       of being canceled or aborted while the job remains in the
       'processing' state, but the marking has not yet stopped so that
       impression or sheet counts are still increasing for the job.

Hastings, et al. Standards Track [Page 115] RFC 2911 IPP/1.1: Model and Semantics September 2000

    'job-canceled-by-user':  The job was canceled by the owner of the
       job using the Cancel-Job request, i.e., by a user whose
       authenticated identity is the same as the value of the
       originating user that created the Job object, or by some other
       authorized end-user, such as a member of the job owner's
       security group.  This value SHOULD be supported.
    'job-canceled-by-operator':  The job was canceled by the operator
       using the Cancel-Job request, i.e., by a user who has been
       authenticated as having operator privileges (whether local or
       remote).  If the security policy is to allow anyone to cancel
       anyone's job, then this value may be used when the job is
       canceled by other than the owner of the job.  For such a
       security policy, in effect, everyone is an operator as far as
       canceling jobs with IPP is concerned.  This value SHOULD be
       supported if the implementation permits canceling by other than
       the owner of the job.
    'job-canceled-at-device':  The job was canceled by an unidentified
       local user, i.e., a user at a console at the device.  This
       value SHOULD be supported if the implementation supports
       canceling jobs at the console.
    'aborted-by-system':  The job (1) is in the process of being
       aborted, (2) has been aborted by the system and placed in the
       'aborted' state, or (3) has been aborted by the system and
       placed in the 'pending-held' state, so that a user or operator
       can manually try the job again.  This value SHOULD be
       supported.
    'unsupported-compression': The job was aborted by the system
       because the Printer determined while attempting to decompress
       the document-data's that the compression is actually not among
       those supported by the Printer.  This value MUST be supported,
       since "compressions is a REQUIRED operation attribute.
    'compression-error': The job was aborted by the system because the
       Printer encountered an error in the document-data while
       decompressing it.  If the Printer posts this reason, the
       document-data has already passed any tests that would have led
       to the 'unsupported-compression' job-state-reason.
    'unsupported-document-format': The job was aborted by the system
       because the document-data's document-format is not among those
       supported by the Printer.  If the client specifies the
       document-format as 'application/octet-stream', the printer MAY
       abort the job and post this reason even though the format is a
       member of the "document-format-supported" printer attribute,
       but not among the auto-sensed document-formats.  This value
       MUST be supported, since "document-format" is a REQUIRED
       operation attribute.

Hastings, et al. Standards Track [Page 116] RFC 2911 IPP/1.1: Model and Semantics September 2000

    'document-format-error': The job was aborted by the system because
       the Printer encountered an error in the document-data while
       processing it.  If the Printer posts this reason, the
       document-data has already passed any tests that would have led
       to the 'unsupported-document-format' job-state-reason.
    'processing-to-stop-point':  The requester has issued a Cancel-Job
       operation or the Printer object has aborted the job, but is
       still performing some actions on the job until a specified stop
       point occurs or job termination/cleanup is completed.
       If the implementation requires some measurable time to cancel
       the job in the 'processing' or 'processing-stopped' job states,
       the IPP object MUST use this value to indicate that the Printer
       object is still performing some actions on the job while the
       job remains in the 'processing' or 'processing-stopped' state.
       After all the job's job description attributes have stopped
       incrementing, the Printer object moves the job from the
       'processing' state to the 'canceled' or
       'aborted' job states.
    'service-off-line':  The Printer is off-line and accepting no
       jobs.  All 'pending' jobs are put into the 'pending-held'
       state.  This situation could be true if the service's or
       document transform's input is impaired or broken.
    'job-completed-successfully':  The job completed successfully.
       This value SHOULD be supported.
    'job-completed-with-warnings':  The job completed with warnings.
       This value SHOULD be supported if the implementation detects
       warnings.
    'job-completed-with-errors':  The job completed with errors (and
       possibly warnings too).  This value SHOULD be supported if the
       implementation detects errors.
    'job-restartable' - This job is retained (see section 4.3.7.2) and
       is currently able to be restarted using the Restart-Job
       operation (see section 3.3.7).  If 'job-restartable' is a value
       of the job's 'job-state-reasons' attribute, then the IPP object
       MUST accept a Restart-Job operation for that job.  This value
       SHOULD be supported if the Restart-Job operation is supported.
    'queued-in-device': The job has been forwarded to a device or
       print system that is unable to send back status.  The Printer
       sets the job's "job-state " attribute to 'completed'  and adds
       the 'queued-in-device' value to the job's "job-state-reasons"
       attribute to indicate that the Printer has no additional
       information about the job and never will have any better
       information.  See section 4.3.7.1.

Hastings, et al. Standards Track [Page 117] RFC 2911 IPP/1.1: Model and Semantics September 2000

4.3.9 job-state-message (text(MAX))

 This attribute specifies information about the "job-state" and "job-
 state-reasons" attributes in human readable text.  If the Printer
 object supports this attribute, the Printer object MUST be able to
 generate this message in any of the natural languages identified by
 the Printer's "generated-natural-language-supported" attribute (see
 the "attributes-natural-language" operation attribute specified in
 Section 3.1.4.1).
 The value SHOULD NOT contain additional information not contained in
 the values of the "job-state" and "job-states-reasons" attributes,
 such as interpreter error information.  Otherwise, application
 programs might attempt to parse the (localized text).  For such
 additional information such as interpreter errors for application
 program consumption or specific document access errors, new
 attributes with keyword values, needs to be developed and registered.

4.3.10 job-detailed-status-messages (1setOf text(MAX))

 This attribute specifies additional detailed and technical
 information about the job.  The Printer NEED NOT localize the
 message(s), since they are intended for use by the system
 administrator or other experienced technical persons.  Localization
 might obscure the technical meaning of such messages.  Clients MUST
 NOT attempt to parse the value of this attribute.  See "job-
 document-access-errors" (section 4.3.11) for additional errors that a
 program can process.

4.3.11 job-document-access-errors (1setOf text(MAX))

 This attribute provides additional information about each document
 access error for this job encountered by the Printer after it
 returned a response to the Print-URI or Send-URI operation and
 subsequently attempted to access document(s) supplied in the Print-
 URI or Send-URI operation.  For errors in the protocol that is
 identified by the URI scheme in the "document-uri" operation
 attribute, such as 'http:' or 'ftp:', the error code is returned in
 parentheses, followed by the URI.  For example:
    (404) http://ftp.pwg.org/pub/pwg/ipp/new_MOD/ipp-model-v11.pdf
 Most Internet protocols use decimal error codes (unlike IPP), so the
 ASCII error code representation is in decimal.

Hastings, et al. Standards Track [Page 118] RFC 2911 IPP/1.1: Model and Semantics September 2000

4.3.12 number-of-documents (integer(0:MAX))

 This attribute indicates the number of documents in the job, i.e.,
 the number of Send-Document, Send-URI, Print-Job, or Print-URI
 operations that the Printer has accepted for this job, regardless of
 whether the document data has reached the Printer object or not.
 Implementations supporting the OPTIONAL Create-Job/Send-
 Document/Send-URI operations SHOULD support this attribute so that
 clients can query the number of documents in each job.

4.3.13 output-device-assigned (name(127))

 This attribute identifies the output device to which the Printer
 object has assigned this job.  If an output device implements an
 embedded Printer object, the Printer object NEED NOT set this
 attribute.  If a print server implements a Printer object, the value
 MAY be empty (zero- length string) or not returned until the Printer
 object assigns an output device to the job.  This attribute is
 particularly useful when a single Printer object supports multiple
 devices (so called "fan-out" - see section 2.1).

4.3.14 Event Time Job Description Attributes

 This section defines the Job Description attributes that indicate the
 time at which certain events occur for a job.  If the job event has
 not yet occurred, then the IPP object MUST return the 'no-value'
 out-of-band value (see the beginning of Section 4.1).  The "time-at-
 xxx(integer)" attributes represent time as an 'integer' representing
 the number of seconds since the device was powered up (informally
 called "time ticks").  The "date-time-at-xxx(dateTime)" attributes
 represent time as 'dateTime' representing date and time (including an
 offset from UTC).
 In order to populate these attributes, the Printer object copies the
 value(s) of the following Printer Description attributes at the time
 the event occurs:
    1. the value in the Printer's "printer-up-time" attribute for the
       "time-at-xxx(integer)" attributes
    2. the value in the Printer's "printer-current-time" attribute for
       the "date-time-at-xxx(dateTime)" attributes.
 If the Printer resets its "printer-up-time" attribute to 1 on power-
 up (see section 4.4.29) and has persistent jobs, then it MUST change
 all of jobs' "time-at-xxx(integer)" (time tick) job attributes whose
 events have occurred either to:

Hastings, et al. Standards Track [Page 119] RFC 2911 IPP/1.1: Model and Semantics September 2000

    1. 0 to indicate that the event happened before the most recent
       power up OR
    2. the negative of the number of seconds before the most recent
       power-up that the event took place, though the negative number
       NEED NOT reflect the exact number of seconds.
 If a client queries a "time-at-xxx(integer)" time tick Job attribute
 and finds the value to be 0 or negative, the client MUST assume that
 the event occurred in some life other than the Printer's current
 life.
 Note: A Printer does not change the values of any "date-time-at-
 xxx(dateTime)" job attributes on power-up.

4.3.14.1 time-at-creation (integer(MIN:MAX))

 This REQUIRED attribute indicates the time at which the Job object
 was created.

4.3.14.2 time-at-processing (integer(MIN:MAX))

 This REQUIRED attribute indicates the time at which the Job object
 first began processing after the create operation or the most recent
 Restart-Job operation.  The out-of-band 'no-value' value is returned
 if the job has not yet been in the 'processing' state (see the
 beginning of Section 4.1).

4.3.14.3 time-at-completed (integer(MIN:MAX))

 This REQUIRED attribute indicates the time at which the Job object
 completed (or was canceled or aborted).  The out-of-band 'no-value'
 value is returned if the job has not yet completed, been canceled, or
 aborted (see the beginning of Section 4.1).

4.3.14.4 job-printer-up-time (integer(1:MAX))

 This REQUIRED Job Description attribute indicates the amount of time
 (in seconds) that the Printer implementation has been up and running.
 This attribute is an alias for the "printer-up-time" Printer
 Description attribute (see Section 4.4.29).
 A client MAY request this attribute in a Get-Job-Attributes or Get-
 Jobs request and use the value returned in combination with other
 requested Event Time Job Description Attributes in order to display
 time attributes to a user.  The difference between this attribute and
 the 'integer' value of a "time-at-xxx" attribute is the number of

Hastings, et al. Standards Track [Page 120] RFC 2911 IPP/1.1: Model and Semantics September 2000

 seconds ago that the "time-at-xxx" event occurred.  A client can
 compute the wall-clock time at which the "time-at-xxx" event occurred
 by subtracting this difference from the client's wall-clock time.

4.3.14.5 date-time-at-creation (dateTime)

 This attribute indicates the date and time at which the Job object
 was created.

4.3.14.6 date-time-at-processing (dateTime)

 This attribute indicates the date and time at which the Job object
 first began processing after the create operation or the most recent
 Restart-Job operation.

4.3.14.7 date-time-at-completed (dateTime)

 This attribute indicates the date and time at which the Job object
 completed (or was canceled or aborted).

4.3.15 number-of-intervening-jobs (integer(0:MAX))

 This attribute indicates the number of jobs that are "ahead" of this
 job in the relative chronological order of expected time to complete
 (i.e., the current scheduled order). For efficiency, it is only
 necessary to calculate this value when an operation is performed that
 requests this attribute.

4.3.16 job-message-from-operator (text(127))

 This attribute provides a message from an operator, system
 administrator or "intelligent" process to indicate to the end user
 the reasons for modification or other management action taken on a
 job.

4.3.17 Job Size Attributes

 This sub-section defines job attributes that describe the size of the
 job.  These attributes are not intended to be counters; they are
 intended to be useful routing and scheduling information if known.
 For these attributes, the Printer object may try to compute the value
 if it is not supplied in the create request.  Even if the client does
 supply a value for these three attributes in the create request, the
 Printer object MAY choose to change the value if the Printer object
 is able to compute a value which is more accurate than the client
 supplied value.  The Printer object may be able to determine the
 correct value for these attributes either right at job submission
 time or at any later point in time.

Hastings, et al. Standards Track [Page 121] RFC 2911 IPP/1.1: Model and Semantics September 2000

4.3.17.1 job-k-octets (integer(0:MAX))

 This attribute specifies the total size of the document(s) in K
 octets, i.e., in units of 1024 octets requested to be processed in
 the job.  The value MUST be rounded up, so that a job between 1 and
 1024 octets MUST be indicated as being 1, 1025 to 2048 MUST be 2,
 etc.
 This value MUST NOT include the multiplicative factors contributed by
 the number of copies specified by the "copies" attribute, independent
 of whether the device can process multiple copies without making
 multiple passes over the job or document data and independent of
 whether the output is collated or not.  Thus the value is independent
 of the implementation and indicates the size of the document(s)
 measured in K octets independent of the number of copies.
 This value MUST also not include the multiplicative factor due to a
 copies instruction embedded in the document data.  If the document
 data actually includes replications of the document data, this value
 will include such replication.  In other words, this value is always
 the size of the source document data, rather than a measure of the
 hardcopy output to be produced.

4.3.17.2 job-impressions (integer(0:MAX))

 This attribute specifies the total size in number of impressions of
 the document(s) being submitted (see the definition of impression in
 section 12.2.5).
 As with "job-k-octets", this value MUST NOT include the
 multiplicative factors contributed by the number of copies specified
 by the "copies" attribute, independent of whether the device can
 process multiple copies without making multiple passes over the job
 or document data and independent of whether the output is collated or
 not.  Thus the value is independent of the implementation and
 reflects the size of the document(s) measured in impressions
 independent of the number of copies.
 As with "job-k-octets", this value MUST also not include the
 multiplicative factor due to a copies instruction embedded in the
 document data.  If the document data actually includes replications
 of the document data, this value will include such replication.  In
 other words, this value is always the number of impressions in the
 source document data, rather than a measure of the number of
 impressions to be produced by the job.

Hastings, et al. Standards Track [Page 122] RFC 2911 IPP/1.1: Model and Semantics September 2000

4.3.17.3 job-media-sheets (integer(0:MAX))

 This attribute specifies the total number of media sheets to be
 produced for this job.
 Unlike the "job-k-octets" and the "job-impressions" attributes, this
 value MUST include the multiplicative factors contributed by the
 number of copies specified by the "copies" attribute and a 'number of
 copies' instruction embedded in the document data, if any.  This
 difference allows the system administrator to control the lower and
 upper bounds of both (1) the size of the document(s) with "job-k-
 octets-supported" and "job-impressions-supported" and (2) the size of
 the job with "job-media-sheets-supported".

4.3.18 Job Progress Attributes

 This sub-section defines job attributes that describe the progress of
 the job.  These attributes are intended to be counters.  That is, the
 value for a job that has not started processing MUST be 0.  When the
 job's "job-state" is 'processing' or 'processing-stopped', this value
 is intended to contain the amount of the job that has been processed
 to the time at which the attributes are requested.  When the job
 enters the 'completed', 'canceled', or 'aborted' states, these values
 are the final values for the job.

4.3.18.1 job-k-octets-processed (integer(0:MAX))

 This attribute specifies the total number of octets processed in K
 octets, i.e., in units of 1024 octets so far.  The value MUST be
 rounded up, so that a job between 1 and 1024 octets inclusive MUST be
 indicated as being 1, 1025 to 2048 inclusive MUST be 2, etc.
 For implementations where multiple copies are produced by the
 interpreter with only a single pass over the data, the final value
 MUST be equal to the value of the "job-k-octets" attribute.  For
 implementations where multiple copies are produced by the interpreter
 by processing the data for each copy, the final value MUST be a
 multiple of the value of the "job-k-octets" attribute.

4.3.18.2 job-impressions-completed (integer(0:MAX))

 This job attribute specifies the number of impressions completed for
 the job so far.  For printing devices, the impressions completed
 includes interpreting, marking, and stacking the output.

Hastings, et al. Standards Track [Page 123] RFC 2911 IPP/1.1: Model and Semantics September 2000

4.3.18.3 job-media-sheets-completed (integer(0:MAX))

 This job attribute specifies the media-sheets completed marking and
 stacking for the entire job so far whether those sheets have been
 processed on one side or on both.

4.3.19 attributes-charset (charset)

 This REQUIRED attribute is populated using the value in the client
 supplied "attributes-charset" attribute in the create request.  It
 identifies the charset (coded character set and encoding method) used
 by any Job attributes with attribute syntax 'text' and 'name' that
 were supplied by the client in the create request.  See Section 3.1.4
 for a complete description of the "attributes-charset" operation
 attribute.
 This attribute does not indicate the charset in which the 'text' and
 'name' values are stored internally in the Job object.  The internal
 charset is implementation-defined.  The IPP object MUST convert from
 whatever the internal charset is to that being requested in an
 operation as specified in Section 3.1.4.

4.3.20 attributes-natural-language (naturalLanguage)

 This REQUIRED attribute is populated using the value in the client
 supplied "attributes-natural-language" attribute in the create
 request.  It identifies the natural language used for any Job
 attributes with attribute syntax 'text' and 'name' that were supplied
 by the client in the create request.  See Section 3.1.4 for a
 complete description of the "attributes-natural-language" operation
 attribute.  See Sections 4.1.1.2 and 4.1.2.2 for how a Natural
 Language Override may be supplied explicitly for each 'text' and
 'name' attribute value that differs from the value identified by the
 "attributes-natural-language" attribute.

4.4 Printer Description Attributes

 These attributes form the attribute group called "printer-
 description".  The following table summarizes these attributes, their
 syntax, and whether or not they are REQUIRED for a Printer object to
 support.  If they are not indicated as REQUIRED, they are OPTIONAL.
 The maximum size in octets for 'text' and 'name' attributes is
 indicated in parenthesizes.
 Note: How these attributes are set by an Administrator is outside the
 scope of this IPP/1.1 document.

Hastings, et al. Standards Track [Page 124] RFC 2911 IPP/1.1: Model and Semantics September 2000

+----------------------------+---------------------------+-----------+
|      Attribute             |     Syntax                | REQUIRED? |
+----------------------------+---------------------------+-----------+
| printer-uri-supported      | 1setOf uri                |  REQUIRED |
+----------------------------+---------------------------+-----------+
| uri-security-supported     | 1setOf type2 keyword      |  REQUIRED |
+----------------------------+---------------------------+-----------+
| uri-authentication-        | 1setOf type2 keyword      |  REQUIRED |
|     supported              |                           |           |
+----------------------------+---------------------------+-----------+
| printer-name               | name (127)                |  REQUIRED |
+----------------------------+---------------------------+-----------+
| printer-location           | text (127)                |           |
+----------------------------+---------------------------+-----------+
| printer-info               | text (127)                |           |
+----------------------------+---------------------------+-----------+
| printer-more-info          | uri                       |           |
+----------------------------+---------------------------+-----------+
| printer-driver-installer   | uri                       |           |
+----------------------------+---------------------------+-----------+
| printer-make-and-model     | text (127)                |           |
+----------------------------+---------------------------+-----------+
| printer-more-info-         | uri                       |           |
| manufacturer               |                           |           |
+----------------------------+---------------------------+-----------+
| printer-state              | type1 enum                |  REQUIRED |
+----------------------------+---------------------------+-----------+
| printer-state-reasons      | 1setOf type2 keyword      |  REQUIRED |
+----------------------------+---------------------------+-----------+
| printer-state-message      | text (MAX)                |           |
+----------------------------+---------------------------+-----------+
| ipp-versions-supported     | 1setOf type2 keyword      |  REQUIRED |
+----------------------------+---------------------------+-----------+
| operations-supported       | 1setOf type2 enum         |  REQUIRED |
+----------------------------+---------------------------+-----------+
| multiple-document-jobs-    | boolean                   |           |
|     supported              |                           |           |
+----------------------------+---------------------------+-----------+
| charset-configured         | charset                   |  REQUIRED |
+----------------------------+---------------------------+-----------+
| charset-supported          | 1setOf charset            |  REQUIRED |
+----------------------------+---------------------------+-----------+
| natural-language-configured| naturalLanguage           |  REQUIRED |
+----------------------------+---------------------------+-----------+
| generated-natural-language-| 1setOf naturalLanguage    |  REQUIRED |
| supported                  |                           |           |
+----------------------------+---------------------------+-----------+
| document-format-default    | mimeMediaType             |  REQUIRED |

Hastings, et al. Standards Track [Page 125] RFC 2911 IPP/1.1: Model and Semantics September 2000

+----------------------------+---------------------------+-----------+
| document-format-supported  | 1setOf mimeMediaType      |  REQUIRED |
+----------------------------+---------------------------+-----------+
| printer-is-accepting-jobs  | boolean                   |  REQUIRED |
+----------------------------+---------------------------+-----------+
| queued-job-count           | integer (0:MAX)           |  REQUIRED |
+----------------------------+---------------------------+-----------+
| printer-message-from-      | text (127)                |           |
| operator                   |                           |           |
+----------------------------+---------------------------+-----------+
| color-supported            | boolean                   |           |
+----------------------------+---------------------------+-----------+
| reference-uri-schemes-     | 1setOf uriScheme          |           |
|   supported                |                           |           |
+----------------------------+---------------------------+-----------+
| pdl-override-supported     | type2 keyword             |  REQUIRED |
+----------------------------+---------------------------+-----------+
| printer-up-time            | integer (1:MAX)           |  REQUIRED |
+----------------------------+---------------------------+-----------+
| printer-current-time       | dateTime                  |           |
+----------------------------+---------------------------+-----------+
| multiple-operation-time-out| integer (1:MAX)           |           |
+----------------------------+---------------------------+-----------+
| compression-supported      | 1setOf type3 keyword      |  REQUIRED |
+----------------------------+---------------------------+-----------+
| job-k-octets-supported     | rangeOfInteger (0:MAX)    |           |
+----------------------------+---------------------------+-----------+
| job-impressions-supported  | rangeOfInteger (0:MAX)    |           |
+----------------------------+---------------------------+-----------+
| job-media-sheets-supported | rangeOfInteger (0:MAX)    |           |
+----------------------------+---------------------------+-----------+
| pages-per-minute           | integer(0:MAX)            |           |
+----------------------------+---------------------------+-----------+
| pages-per-minute-color     | integer(0:MAX)            |           |
+----------------------------+---------------------------+-----------+

4.4.1 printer-uri-supported (1setOf uri)

 This REQUIRED Printer attribute contains at least one URI for the
 Printer object.  It OPTIONALLY contains more than one URI for the
 Printer object.    An administrator determines a Printer object's
 URI(s) and configures this attribute to contain those URIs by some
 means outside the scope of this IPP/1.1 document.  The precise format
 of this URI is implementation dependent and depends on the protocol.
 See the next two sections for a description of the "uri-security-
 supported" and "uri-authentication-supported" attributes, both of

Hastings, et al. Standards Track [Page 126] RFC 2911 IPP/1.1: Model and Semantics September 2000

 which are the REQUIRED companion attributes to this "printer-uri-
 supported" attribute.  See section 2.4 on Printer object identity and
 section 8.2 on security and URIs for more information.

4.4.2 uri-authentication-supported (1setOf type2 keyword)

 This REQUIRED Printer attribute MUST have the same cardinality
 (contain the same number of values) as the "printer-uri-supported"
 attribute.  This attribute identifies the Client Authentication
 mechanism associated with each URI listed in the "printer-uri-
 supported" attribute. The Printer object uses the specified mechanism
 to identify the authenticated user (see section 8.3).  The "i th"
 value in "uri-authentication-supported" corresponds to the "i th"
 value in "printer-uri-supported" and it describes the authentication
 mechanisms used by the Printer when accessed via that URI.  See
 [RFC2910] for more details on Client Authentication.
 The following standard keyword values are defined:
    'none': There is no authentication mechanism associated with the
       URI.  The Printer object assumes that the authenticated user is
       "anonymous".
    'requesting-user-name': When a client performs an operation whose
       target is the associated URI, the Printer object assumes that
       the authenticated user is specified by the "requesting-user-
       name" Operation attribute (see section 8.3). If the
       "requesting-user-name" attribute is absent in a request, the
       Printer object assumes that the authenticated user is
       "anonymous".
    'basic': When a client performs an operation whose target is the
       associated URI, the Printer object challenges the client with
       HTTP basic authentication [RFC2617]. The Printer object assumes
       that the authenticated user is the name received via the basic
       authentication mechanism.
    'digest': When a client performs an operation whose target is the
       associated URI, the Printer object challenges the client with
       HTTP digest authentication [RFC2617]. The Printer object
       assumes that the authenticated user is the name received via
       the digest authentication mechanism.
    'certificate': When a client performs an operation whose target is
       the associated URI, the Printer object expects the client to
       provide a certificate. The Printer object assumes that the
       authenticated user is the textual name contained within the
       certificate.

Hastings, et al. Standards Track [Page 127] RFC 2911 IPP/1.1: Model and Semantics September 2000

4.4.3 uri-security-supported (1setOf type2 keyword)

 This REQUIRED Printer attribute MUST have the same cardinality
 (contain the same number of values) as the "printer-uri-supported"
 attribute.  This attribute identifies the security mechanisms used
 for each URI listed in the "printer-uri-supported" attribute.  The "i
 th" value in "uri-security-supported" corresponds to the "i th" value
 in "printer-uri-supported" and it describes the security mechanisms
 used for accessing the Printer object via that URI.  See [RFC2910]
 for more details on security mechanisms.
 The following standard keyword values are defined:
    'none': There are no secure communication channel protocols in use
       for the given URI.
    'ssl3': SSL3 [SSL] is the secure communications channel protocol
       in use for the given URI.
    'tls':  TLS [RFC2246] is the secure communications channel
       protocol in use for the given URI.
 This attribute is orthogonal to the definition of a Client
 Authentication mechanism.  Specifically, 'none' does not exclude
 Client Authentication. See section 4.4.2.
 Consider the following example.  For a single Printer object, an
 administrator configures the "printer-uri-supported",  "uri-
 authentication-supported" and "uri-security-supported" attributes as
 follows:
   "printer-uri-supported": 'xxx://acme.com/open-use-printer',
      'xxx://acme.com/restricted-use-printer',
      'xxx://acme.com/private-printer'
   "uri-authentication-supported": 'none', 'digest', 'basic'
   "uri-security-supported": 'none', 'none', 'tls'
 Note:  'xxx'  is not a valid scheme.  See the IPP/1.1 "Transport and
 Encoding" document [RFC2910] for the actual URI schemes to be used in
 object target attributes.
 In this case, one Printer object has three URIs.
  1. For the first URI, 'xxx:acme.com/open-use-printer', the value 'none' in "uri-security-supported" indicates that there is no secure channel protocol configured to run under HTTP. The value of 'none' in "uri-authentication-supported" indicates that all users are 'anonymous'. There will be no challenge and the Printer will ignore "requesting-user-name". Hastings, et al. Standards Track [Page 128] RFC 2911 IPP/1.1: Model and Semantics September 2000 - For the second URI, 'xxx:acme.com/restricted-use-printer', the

value 'none' in "uri-security-supported" indicates that there is

      no secure channel protocol configured to run under HTTP. The
      value of 'digest' in "uri-authentication-supported" indicates
      that the Printer will issue a challenge and that the Printer
      will use the name supplied by the digest mechanism to determine
      the authenticated user (see section 8.3).
    - For the third URI, 'xxx://acme.com/private-printer', the value
      'tls' in "uri-security-supported" indicates that TLS is being
      used to secure the channel.  The client SHOULD be prepared to
      use TLS framing to negotiate an acceptable ciphersuite to use
      while communicating with the Printer object.  In this case, the
      name implies the use of a secure communications channel, but the
      fact is made explicit by the presence of the 'tls' value in
      "uri-security-supported".  The client does not need to resort to
      understanding which security it must use by following naming
      conventions or by parsing the URI to determine which security
      mechanisms are implied.  The value of 'basic' in "uri-
      authentication-supported" indicates that the Printer will issue
      a challenge and that the Printer will use the name supplied by
      the digest mechanism to determine the authenticated user (see
      section 8.3).  Because this challenge occurs in a tls session,
      the channel is secure.
 It is expected that many IPP Printer objects will be configured to
 support only one channel (either configured to use TLS access or not)
 and only one authentication mechanism. Such Printer objects only have
 one URI listed in the "printer-uri-supported" attribute.  No matter
 the configuration of the Printer object (whether it has only one URI
 or more than one URI), a client MUST supply only one URI in the
 target "printer-uri" operation attribute.

4.4.4 printer-name (name(127))

 This REQUIRED Printer attribute contains the name of the Printer
 object.  It is a name that is more end-user friendly than a URI. An
 administrator determines a printer's name and sets this attribute to
 that name. This name may be the last part of the printer's URI or it
 may be unrelated.  In non-US-English locales, a name may contain
 characters that are not allowed in a URI.

4.4.5 printer-location (text(127))

 This Printer attribute identifies the location of the device. This
 could include things like: "in Room 123A, second floor of building
 XYZ".

Hastings, et al. Standards Track [Page 129] RFC 2911 IPP/1.1: Model and Semantics September 2000

4.4.6 printer-info (text(127))

 This Printer attribute identifies the descriptive information about
 this Printer object.  This could include things like: "This printer
 can be used for printing color transparencies for HR presentations",
 or "Out of courtesy for others, please print only small (1-5 page)
 jobs at this printer", or even "This printer is going away on July 1,
 1997, please find a new printer".

4.4.7 printer-more-info (uri)

 This Printer attribute contains a URI used to obtain more information
 about this specific Printer object.  For example, this could be an
 HTTP type URI referencing an HTML page accessible to a Web Browser.
 The information obtained from this URI is intended for end user
 consumption.  Features outside the scope of IPP can be accessed from
 this URI.  The information is intended to be specific to this printer
 instance and site specific services (e.g. job pricing, services
 offered, end user assistance). The device manufacturer may initially
 populate this attribute.

4.4.8 printer-driver-installer (uri)

 This Printer attribute contains a URI to use to locate the driver
 installer for this Printer object.   This attribute is intended for
 consumption by automata.  The mechanics of print driver installation
 is outside the scope of this IPP/1.1 document.  The device
 manufacturer may initially populate this attribute.

4.4.9 printer-make-and-model (text(127))

 This Printer attribute identifies the make and model of the device.
 The device manufacturer may initially populate this attribute.

4.4.10 printer-more-info-manufacturer (uri)

 This Printer attribute contains a URI used to obtain more information
 about this type of device.  The information obtained from this URI is
 intended for end user consumption.  Features outside the scope of IPP
 can be accessed from this URI (e.g., latest firmware, upgrades, print
 drivers, optional features available, details on color support).  The
 information is intended to be germane to this printer without regard
 to site specific modifications or services. The device manufacturer
 may initially populate this attribute.

Hastings, et al. Standards Track [Page 130] RFC 2911 IPP/1.1: Model and Semantics September 2000

4.4.11 printer-state (type1 enum)

 This REQUIRED Printer attribute identifies the current state of the
 device.  The "printer-state reasons" attribute augments the
 "printer-state" attribute to give more detailed information about the
 Printer in the given printer state.
 A Printer object need only update this attribute before responding to
 an operation which requests the attribute; the Printer object NEED
 NOT update this attribute continually, since asynchronous event
 notification is not part of IPP/1.1.  A Printer NEED NOT implement
 all values if they are not applicable to a given implementation.
 The following standard enum values are defined:
 Value  Symbolic Name and Description
 '3'    'idle':  Indicates that new jobs can start processing without
              waiting.
 '4'    'processing':  Indicates that jobs are processing; new jobs
              will wait before processing.
 '5'    'stopped':  Indicates that no jobs can be processed and
              intervention is required.
 Values of "printer-state-reasons", such as 'spool-area-full' and
 'stopped-partly', MAY be used to provide further information.

4.4.12 printer-state-reasons (1setOf type2 keyword)

 This REQUIRED Printer attribute supplies additional detail about the
 device's state.  Some of the these value definitions indicate
 conformance requirements; the rest are OPTIONAL.
 Each keyword value MAY have a suffix to indicate its level of
 severity.  The three levels are: report (least severe), warning, and
 error (most severe).
  1. '-report': This suffix indicates that the reason is a "report".

An implementation may choose to omit some or all reports. Some

      reports specify finer granularity about the printer state;
      others serve as a precursor to a warning. A report MUST contain
      nothing that could affect the printed output.
    - '-warning': This suffix indicates that the reason is a
      "warning".  An implementation may choose to omit some or all
      warnings. Warnings serve as a precursor to an error. A warning
      MUST contain nothing that prevents a job from completing, though
      in some cases the output may be of lower quality.

Hastings, et al. Standards Track [Page 131] RFC 2911 IPP/1.1: Model and Semantics September 2000

  1. '-error': This suffix indicates that the reason is an "error".

An implementation MUST include all errors. If this attribute

      contains one or more errors, printer MUST be in the stopped
      state.
 If the implementation does not add any one of the three suffixes, all
 parties MUST assume that the reason is an "error".
 If a Printer object controls more than one output device, each value
 of this attribute MAY apply to one or more of the output devices.  An
 error on one output device that does not stop the Printer object as a
 whole MAY appear as a warning in the Printer's "printer-state-reasons
 attribute".  If the "printer-state" for such a Printer has a value of
 'stopped', then there MUST be an error reason among the values in the
 "printer-state-reasons" attribute.
 The following standard keyword values are defined:
    'other': The device has detected an error other than one listed in
       this document.
    'none': There are not reasons. This state reason is semantically
       equivalent to "printer-state-reasons" without any value and
       MUST be used, since the 1setOf attribute syntax requires at
       least one value.
    'media-needed': A tray has run out of media.
    'media-jam': The device has a media jam.
    'moving-to-paused':  Someone has paused the Printer object using
       the Pause-Printer operation (see section 3.2.7) or other means,
       but the device(s) are taking an appreciable time to stop.
       Later, when all output has stopped, the "printer-state" becomes
       'stopped', and the 'paused' value replaces the 'moving-to-
       paused' value in the "printer-state-reasons" attribute.  This
       value MUST be supported, if the Pause-Printer operation is
       supported and the implementation takes significant time to
       pause a device in certain circumstances.
    'paused': Someone has paused the Printer object using the Pause-
       Printer operation (see section 3.2.7) or other means and the
       Printer object's "printer-state" is 'stopped'.  In this state,
       a Printer MUST NOT produce printed output, but it MUST perform
       other operations requested by a client.  If a Printer had been
       printing a job when the Printer was paused, the Printer MUST
       resume printing that job when the Printer is no longer paused
       and leave no evidence in the printed output of such a pause.
       This value MUST be supported, if the Pause-Printer operation is
       supported.
    'shutdown': Someone has removed a Printer object from service, and
       the device may be powered down or physically removed.  In this
       state, a Printer object MUST NOT produce printed output, and

Hastings, et al. Standards Track [Page 132] RFC 2911 IPP/1.1: Model and Semantics September 2000

       unless the Printer object is realized by a print server that is
       still active, the Printer object MUST perform no other
       operations requested by a client, including returning this
       value. If a Printer object had been printing a job when it was
       shutdown, the Printer NEED NOT resume printing that job when
       the Printer is no longer shutdown. If the Printer resumes
       printing such a job, it may leave evidence in the printed
       output of such a shutdown, e.g. the part printed before the
       shutdown may be printed a second time after the shutdown.
    'connecting-to-device': The Printer object has scheduled a job on
       the output device and is in the process of connecting to a
       shared network output device (and might not be able to actually
       start printing the job for an arbitrarily long time depending
       on the usage of the output device by other servers on the
       network).
    'timed-out': The server was able to connect to the output device
       (or is always connected), but was unable to get a response from
       the output device.
    'stopping': The Printer object is in the process of stopping the
       device and will be stopped in a while. When the device is
       stopped, the Printer object will change the Printer object's
       state to 'stopped'.  The 'stopping-warning' reason is never an
       error, even for a Printer with a single output device.  When an
       output-device ceases accepting jobs, the Printer will have this
       reason while the output device completes printing.
    'stopped-partly': When a Printer object controls more than one
       output device, this reason indicates that one or more output
       devices are stopped.  If the reason is a report, fewer than
       half of the output devices are stopped.  If the reason is a
       warning, fewer than all of the output devices are stopped.
    'toner-low': The device is low on toner.
    'toner-empty':  The device is out of toner.
    'spool-area-full': The limit of persistent storage allocated for
       spooling has been reached.  The Printer is temporarily unable
       to accept more jobs.  The Printer will remove this value when
       it is able to accept more jobs.  This value SHOULD be used by a
       non-spooling Printer that only accepts one or a small number
       jobs at a time or a spooling Printer that has filled the spool
       space.
    'cover-open': One or more covers on the device are open.
    'interlock-open': One or more interlock devices on the printer are
       unlocked.
    'door-open': One or more doors on the device are open.
    'input-tray-missing': One or more input trays are not in the
       device.
    'media-low': At least one input tray is low on media.
    'media-empty': At least one input tray is empty.

Hastings, et al. Standards Track [Page 133] RFC 2911 IPP/1.1: Model and Semantics September 2000

    'output-tray-missing': One or more output trays are not in the
       device
    'output-area-almost-full': One or more output area is almost full
       (e.g. tray, stacker, collator).
    'output-area-full': One or more output area is full. (e.g. tray,
       stacker, collator)
    'marker-supply-low': The device is low on at least one marker
       supply.  (e.g. toner, ink, ribbon)
    'marker-supply-empty: The device is out of at least one marker
       supply. (e.g. toner, ink, ribbon)
    'marker-waste-almost-full': The device marker supply waste
       receptacle is almost full.
    'marker-waste-full': The device marker supply waste receptacle is
       full.
    'fuser-over-temp': The fuser temperature is above normal.
    'fuser-under-temp': The fuser temperature is below normal.
    'opc-near-eol': The optical photo conductor is near end of life.
    'opc-life-over': The optical photo conductor is no longer
       functioning.
    'developer-low': The device is low on developer.
    'developer-empty: The device is out of developer.
    'interpreter-resource-unavailable': An interpreter resource is
       unavailable (i.e. font, form)

4.4.13 printer-state-message (text(MAX))

 This Printer attribute specifies information about the "printer-
 state" and "printer-state-reasons" attributes in human readable text.
 If the Printer object supports this attribute, the Printer object
 MUST be able to generate this message in any of the natural languages
 identified by the Printer's "generated-natural-language-supported"
 attribute (see the "attributes-natural-language" operation attribute
 specified in Section 3.1.4.1).

4.4.14 ipp-versions-supported (1setOf type2 keyword)

 This REQUIRED attribute identifies the IPP protocol version(s) that
 this Printer supports, including major and minor versions, i.e., the
 version numbers for which this Printer implementation meets the
 conformance requirements.  For version number validation, the Printer
 matches the (two-octet binary) "version-number" parameter supplied by
 the client in each request (see sections 3.1.1 and 3.1.8) with the
 (US-ASCII) keyword values of this attribute.

Hastings, et al. Standards Track [Page 134] RFC 2911 IPP/1.1: Model and Semantics September 2000

 The following standard keyword values are defined:
    '1.0': Meets the conformance requirement of IPP version 1.0 as
       specified in RFC 2566 [RFC2566] and RFC 2565 [RFC2565]
       including any extensions registered according to Section 6 and
       any extension defined in this version or any future version of
       the IPP "Model and Semantics" document or the IPP "Encoding and
       Transport" document following the rules, if any, when the
       "version-number" parameter is '1.0'.
    '1.1': Meets the conformance requirement of IPP version 1.1 as
       specified in this document and [RFC2910] including any
       extensions registered according to Section 6 and any extension
       defined in any future versions of the IPP "Model and Semantics"
       document or the IPP Encoding and Transport document following
       the rules, if any, when the "version-number" parameter is
       '1.1'.

4.4.15 operations-supported (1setOf type2 enum)

 This REQUIRED Printer attribute specifies the set of supported
 operations for this Printer object and contained Job objects.
 This attribute is encoded as any other enum attribute syntax
 according to [RFC2910] as 32-bits.  However, all 32-bit enum values
 for this attribute MUST NOT exceed 0x00008FFF, since these same
 values are also passed in two octets in the "operation-id" parameter
 (see section 3.1.1) in each Protocol request with the two high order
 octets omitted in order to indicate the operation being performed
 [RFC2910].
 The following standard enum and "operation-id" (see section 3.1.2)
 values are defined:

Hastings, et al. Standards Track [Page 135] RFC 2911 IPP/1.1: Model and Semantics September 2000

   Value               Operation Name
   -----------------   -------------------------------------
   0x0000              reserved, not used
   0x0001              reserved, not used
   0x0002              Print-Job
   0x0003              Print-URI
   0x0004              Validate-Job
   0x0005              Create-Job
   0x0006              Send-Document
   0x0007              Send-URI
   0x0008              Cancel-Job
   0x0009              Get-Job-Attributes
   0x000A              Get-Jobs
   0x000B              Get-Printer-Attributes
   0x000C              Hold-Job
   0x000D              Release-Job
   0x000E              Restart-Job
   0x000F              reserved for a future operation
   0x0010              Pause-Printer
   0x0011              Resume-Printer
   0x0012              Purge-Jobs
   0x0013-0x3FFF       reserved for future IETF standards track
                       operations (see section 6.4)
   0x4000-0x8FFF       reserved for vendor extensions (see section 6.4)

4.4.16 multiple-document-jobs-supported (boolean)

 This Printer attribute indicates whether or not the Printer supports
 more than one document per job, i.e., more than one Send-Document or
 Send-Data operation with document data.  If the Printer supports the
 Create-Job and Send-Document operations (see section 3.2.4 and
 3.3.1), it MUST support this attribute.

4.4.17 charset-configured (charset)

 This REQUIRED Printer attribute identifies the charset that the
 Printer object has been configured to represent 'text' and 'name'
 Printer attributes that are set by the operator, system
 administrator, or manufacturer, i.e., for "printer-name" (name),
 "printer-location" (text), "printer-info" (text), and "printer-make-
 and-model" (text).  Therefore, the value of the Printer object's
 "charset-configured" attribute MUST also be among the values of the
 Printer object's "charset-supported" attribute.

Hastings, et al. Standards Track [Page 136] RFC 2911 IPP/1.1: Model and Semantics September 2000

4.4.18 charset-supported (1setOf charset)

 This REQUIRED Printer attribute identifies the set of charsets that
 the Printer and contained Job objects support in attributes with
 attribute syntax 'text' and 'name'. At least the value 'utf-8' MUST
 be present, since IPP objects MUST support the UTF-8 [RFC2279]
 charset.  If a Printer object supports a charset, it means that for
 all attributes of syntax 'text' and 'name' the IPP object MUST (1)
 accept the charset in requests and return the charset in responses as
 needed.
 If more charsets than UTF-8 are supported, the IPP object MUST
 perform charset conversion between the charsets as described in
 Section 3.1.4.2.

4.4.19 natural-language-configured (naturalLanguage)

 This REQUIRED Printer attribute identifies the natural language that
 the Printer object has been configured to represent 'text' and 'name'
 Printer attributes that are set by the operator, system
 administrator, or manufacturer, i.e., for "printer-name" (name),
 "printer-location" (text), "printer-info" (text), and "printer-make-
 and-model" (text).  When returning these Printer attributes, the
 Printer object MAY return them in the configured natural language
 specified by this attribute, instead of the natural language
 requested by the client in the "attributes-natural-language"
 operation attribute.  See Section 3.1.4.1 for the specification of
 the OPTIONAL multiple natural language support.  Therefore, the value
 of the Printer object's "natural-language-configured" attribute MUST
 also be among the values of the Printer object's "generated-natural-
 language-supported" attribute.

4.4.20 generated-natural-language-supported (1setOf naturalLanguage)

 This REQUIRED Printer attribute identifies the natural language(s)
 that the Printer object and contained Job objects support in
 attributes with attribute syntax 'text' and 'name'.  The natural
 language(s) supported depends on implementation and/or configuration.
 Unlike charsets, IPP objects MUST accept requests with any natural
 language or any Natural Language Override whether the natural
 language is supported or not.
 If a Printer object supports a natural language, it means that for
 any of the attributes for which the Printer or Job object generates
 messages, i.e., for the "job-state-message" and "printer-state-
 message" attributes and Operation Messages (see Section 3.1.5) in
 operation responses, the Printer and Job objects MUST be able to

Hastings, et al. Standards Track [Page 137] RFC 2911 IPP/1.1: Model and Semantics September 2000

 generate messages in any of the Printer's supported natural
 languages.  See section 3.1.4 for the definition of 'text' and 'name'
 attributes in operation requests and responses.
 Note: A Printer object that supports multiple natural languages,
 often has separate catalogs of messages, one for each natural
 language supported.

4.4.21 document-format-default (mimeMediaType)

 This REQUIRED Printer attribute identifies the document format that
 the Printer object has been configured to assume if the client does
 not supply a "document-format" operation attribute in any of the
 operation requests that supply document data.  The standard values
 for this attribute are Internet Media types (sometimes called MIME
 types).  For further details see the description of the
 'mimeMediaType' attribute syntax in Section 4.1.9.

4.4.22 document-format-supported (1setOf mimeMediaType)

 This REQUIRED Printer attribute identifies the set of document
 formats that the Printer object and contained Job objects can
 support. For further details see the description of the
 'mimeMediaType' attribute syntax in Section 4.1.9.

4.4.23 printer-is-accepting-jobs (boolean)

 This REQUIRED Printer attribute indicates whether the printer is
 currently able to accept jobs, i.e., is accepting Print-Job, Print-
 URI, and Create-Job requests.  If the value is 'true', the printer is
 accepting jobs.  If the value is 'false', the Printer object is
 currently rejecting any jobs submitted to it.  In this case, the
 Printer object returns the 'server-error-not-accepting-jobs' status
 code.
 This value is independent of the "printer-state" and "printer-state-
 reasons" attributes because its value does not affect the current
 job; rather it affects future jobs.  This attribute, when 'false',
 causes the Printer to reject jobs even when the "printer-state" is
 'idle' or, when 'true', causes the Printer object to accepts jobs
 even when the "printer-state" is 'stopped'.

4.4.24 queued-job-count (integer(0:MAX))

 This REQUIRED Printer attribute contains a count of the number of
 jobs that are either 'pending', 'processing', 'pending-held', or
 'processing-stopped' and is set by the Printer object.

Hastings, et al. Standards Track [Page 138] RFC 2911 IPP/1.1: Model and Semantics September 2000

4.4.25 printer-message-from-operator (text(127))

 This Printer attribute provides a message from an operator, system
 administrator or "intelligent" process to indicate to the end user
 information or status of the printer, such as why it is unavailable
 or when it is expected to be available.

4.4.26 color-supported (boolean)

 This Printer attribute identifies whether the device is capable of
 any type of color printing at all, including highlight color.  All
 document instructions having to do with color are embedded within the
 document PDL (none are external IPP attributes in IPP/1.1).
 Note:  end-users are able to determine the nature and details of the
 color support by querying the "printer-more-info-manufacturer"
 Printer attribute.

4.4.27 reference-uri-schemes-supported (1setOf uriScheme)

 This Printer attribute specifies which URI schemes are supported for
 use in the "document-uri" operation attribute of the Print-URI or
 Send-URI operation.  If a Printer object supports these optional
 operations, it MUST support the "reference-uri-schemes-supported"
 Printer attribute with at least the following schemed URI value:
    'ftp':  The Printer object will use an FTP 'get' operation as
       defined in RFC 2228 [RFC2228] using FTP URLs as defined by
       [RFC2396] and [RFC2316].
 The Printer object MAY OPTIONALLY support other URI schemes (see
 section 4.1.6).

4.4.28 pdl-override-supported (type2 keyword)

 This REQUIRED Printer attribute expresses the ability for a
 particular Printer implementation to either attempt to override
 document data instructions with IPP attributes or not.
 This attribute takes on the following keyword values:
  1. 'attempted': This value indicates that the Printer object

attempts to make the IPP attribute values take precedence over

       embedded instructions in the document data, however there is no
       guarantee.
    - 'not-attempted': This value indicates that the Printer object
       makes no attempt to make the IPP attribute values take
       precedence over embedded instructions in the document data.

Hastings, et al. Standards Track [Page 139] RFC 2911 IPP/1.1: Model and Semantics September 2000

 Section 15 contains a full description of how this attribute
 interacts with and affects other IPP attributes, especially the
 "ipp-attribute-fidelity" attribute.

4.4.29 printer-up-time (integer(1:MAX))

 This REQUIRED Printer attribute indicates the amount of time (in
 seconds) that this Printer instance has been up and running.  The
 value is a monotonically increasing value starting from 1 when the
 Printer object is started-up (initialized, booted, etc.).  This value
 is used to populate the Event Time Job Description Job attributes
 "time-at-creation", "time-at-processing", and "time-at-completed"
 (see section 4.3.14).
 If the Printer object goes down at some value 'n', and comes back up,
 the implementation MAY:
    1. Know how long it has been down, and resume at some value
       greater than 'n', or
    2. Restart from 1.
 In other words, if the device or devices that the Printer object is
 representing are restarted or power cycled, the Printer object MAY
 continue counting this value or MAY reset this value to 1 depending
 on implementation.  However, if the Printer object software ceases
 running, and restarts without knowing the last value for "printer-
 up-time", the implementation MUST reset this value to 1.  If this
 value is reset and the Printer has persistent jobs, the Printer MUST
 reset the "time-at-xxx(integer) Event Time Job Description attributes
 according to Section 4.3.14.  An implementation MAY use both
 implementation alternatives, depending on warm versus cold start,
 respectively.

4.4.30 printer-current-time (dateTime)

 This Printer attribute indicates the current date and time.  This
 value is used to populate the Event Time Job Description attributes:
 "date-time-at-creation", "date-time-at-processing", and "date-time-
 at-completed" (see Section 4.3.14).
 The date and time is obtained on a "best efforts basis" and does not
 have to be that precise in order to work in practice.  A Printer
 implementation sets the value of this attribute by obtaining the date
 and time via some implementation-dependent means, such as getting the
 value from a network time server, initialization at time of
 manufacture, or setting by an administrator.  See [IPP-IIG] for
 examples.  If an implementation supports this attribute and the
 implementation knows that it has not yet been set, then the

Hastings, et al. Standards Track [Page 140] RFC 2911 IPP/1.1: Model and Semantics September 2000

 implementation MUST return the value of this attribute using the
 out-of-band 'no-value' meaning not configured.  See the beginning of
 section 4.1.
 The time zone of this attribute NEED NOT be the time zone used by
 people located near the Printer object or device.  The client MUST
 NOT expect that the time zone of any received 'dateTime' value to be
 in the time zone of the client or in the time zone of the people
 located near the printer.
 The client SHOULD display any dateTime attributes to the user in
 client local time by converting the 'dateTime' value returned by the
 server to the time zone of the client, rather than using the time
 zone returned by the Printer in attributes that use the 'dateTime'
 attribute syntax.

4.4.31 multiple-operation-time-out (integer(1:MAX))

 This Printer attributes identifies the minimum time (in seconds) that
 the Printer object waits for additional Send-Document or Send-URI
 operations to follow a still-open Job object before taking  any
 recovery actions, such as the ones indicated in section 3.3.1.  If
 the Printer object supports the Create-Job and Send-Document
 operations (see section 3.2.4 and 3.3.1), it MUST support this
 attribute.
 It is RECOMMENDED that vendors supply a value for this attribute that
 is between 60 and 240 seconds.  An implementation MAY allow a system
 administrator to set this attribute (by means outside this IPP/1.1
 document).  If so, the system administrator MAY be able to set values
 outside this range.

4.4.32 compression-supported (1setOf type3 keyword)

 This REQUIRED Printer attribute identifies the set of supported
 compression algorithms for document data.  Compression only applies
 to the document data; compression does not apply to the encoding of
 the IPP operation itself.  The supported values are used to validate
 the client supplied "compression" operation attributes in Print-Job,
 Send-Document, and Send-URI requests.
 Standard keyword values are :
 'none': no compression is used.
 'deflate':  ZIP public domain inflate/deflate) compression technology
    in RFC 1951 [RFC1951]
 'gzip' GNU zip compression technology described in RFC 1952
    [RFC1952].

Hastings, et al. Standards Track [Page 141] RFC 2911 IPP/1.1: Model and Semantics September 2000

 'compress': UNIX compression technology in RFC 1977 [RFC1977]

4.4.33 job-k-octets-supported (rangeOfInteger(0:MAX))

 This Printer attribute specifies the upper and lower bounds of total
 sizes of jobs in K octets, i.e., in units of 1024 octets. The
 supported values are used to validate the client supplied "job-k-
 octets" operation attributes in create requests.  The corresponding
 job description attribute "job-k-octets" is defined in section
 4.3.17.1.

4.4.34 job-impressions-supported (rangeOfInteger(0:MAX))

 This Printer attribute specifies the upper and lower bounds for the
 number of impressions per job. The supported values are used to
 validate the client supplied "job-impressions" operation attributes
 in create requests.  The corresponding job description attribute
 "job-impressions" is defined in section 4.3.17.2.

4.4.35 job-media-sheets-supported (rangeOfInteger(0:MAX))

 This Printer attribute specifies the upper and lower bounds for the
 number of media sheets per job. The supported values are used to
 validate the client supplied "job-media-sheets" operation attributes
 in create requests.  The corresponding Job attribute "job-media-
 sheets" is defined in section 4.3.17.3.

4.4.36 pages-per-minute (integer(0:MAX))

 This Printer attributes specifies the nominal number of pages per
 minute to the nearest whole number which may be generated by this
 printer (e.g., simplex, black-and-white).  This attribute is
 informative, not a service guarantee.  Generally, it is the value
 used in the marketing literature to describe the device.
 A value of 0 indicates a device that takes more than two minutes to
 process a page.

4.4.37 pages-per-minute-color (integer(0:MAX))

 This Printer attributes specifies the nominal number of pages per
 minute to the nearest whole number which may be generated by this
 printer when printing color (e.g., simplex, color).  For purposes of
 this attribute, "color" means the same as for the "color-supported"
 attribute, namely, the device is capable of any type of color
 printing at all, including highlight color.  This attribute is

Hastings, et al. Standards Track [Page 142] RFC 2911 IPP/1.1: Model and Semantics September 2000

 informative, not a service guarantee.  Generally, it is the value
 used in the marketing literature to describe the color capabilities
 of this device.
 A value of 0 indicates a device that takes more than two minutes to
 process a page.
 If a color device has several color modes, it MAY use the pages-per-
 minute value for this attribute that corresponds to the mode that
 produces the highest number.
 Black and white only printers MUST NOT support this attribute.  If
 this attribute is present, then the "color-supported" Printer
 description attribute MUST be present and have a 'true' value.
 The values of these two attributes returned by the Get-Printer-
 Attributes operation MAY be affected by the "document-format"
 attribute supplied by the client in the Get-Printer-Attributes
 request.  In other words, the implementation MAY have different
 speeds depending on the document format being processed.  See section
 3.2.5.1 Get-Printer-Attributes.

5. Conformance

 This section describes conformance issues and requirements. This
 document introduces model entities such as objects, operations,
 attributes, attribute syntaxes, and attribute values.  These
 conformance sections describe the conformance requirements which
 apply to these model entities.

5.1 Client Conformance Requirements

 This section describes the conformance requirements for a client (see
 section 2.1), whether it be:
    1. contained within software controlled by an end user, e.g.
       activated by the "Print" menu item in an application that sends
       IPP requests or
    2. the print server component that sends IPP requests to either an
       output device or another "downstream" print server.
 A conforming client MUST support all REQUIRED operations as defined
 in this document.  For each attribute included in an operation
 request, a conforming client MUST supply a value whose type and value
 syntax conforms to the requirements of the Model document as
 specified in Sections 3 and 4.  A conforming client MAY supply any

Hastings, et al. Standards Track [Page 143] RFC 2911 IPP/1.1: Model and Semantics September 2000

 IETF standards track extensions and/or vendor extensions in an
 operation request, as long as the extensions meet the requirements in
 Section 6.
 Otherwise, there are no conformance requirements placed on the user
 interfaces provided by IPP clients or their applications.  For
 example, one application might not allow an end user to submit
 multiple documents per job, while another does.  One application
 might first query a Printer object in order to supply a graphical
 user interface (GUI) dialogue box with supported and default values
 whereas a different implementation might not.
 When sending a request, an IPP client NEED NOT supply any attributes
 that are indicated as OPTIONALLY supplied by the client.
 A client MUST be able to accept any of the attribute syntaxes defined
 in Section 4.1, including their full range, that may be returned to
 it in a response from a Printer object.  In particular for each
 attribute that the client supports whose attribute syntax is 'text',
 the client MUST accept and process both the 'textWithoutLanguage' and
 'textWithLanguage' forms.  Similarly, for each attribute that the
 client supports whose attribute syntax is 'name', the client MUST
 accept and process both the 'nameWithoutLanguage' and
 'nameWithLanguage' forms.  For presentation purposes, truncation of
 long attribute values is not recommended.  A recommended approach
 would be for the client implementation to allow the user to scroll
 through long attribute values.
 A response MAY contain attribute groups, attributes, attribute
 syntaxes, values, and status codes that the client does not expect.
 Therefore, a client implementation MUST gracefully handle such
 responses and not refuse to inter-operate with a conforming Printer
 that is returning IETF standards track extension or vendor
 extensions, including attribute groups, attributes, attribute
 syntaxes, attribute values, status codes, and out-of-band attribute
 values that conform to Section 6.  Clients may choose to ignore any
 parameters, attribute groups, attributes, attribute syntaxes, or
 values that they do not understand.
 While a client is sending data to a printer, it SHOULD do its best to
 prevent a channel from being closed by a lower layer when the channel
 is blocked (i.e. flow-controlled off) for whatever reason, e.g. 'out
 of paper' or 'job ahead hasn't freed up enough memory'.  However, the
 layer that launched the print submission (e.g. an end user) MAY close
 the channel in order to cancel the job.  When a client closes a
 channel, a Printer MAY print all or part of the received portion of
 the document.  See the "Encoding and Transport" document [RFC2910]
 for more details.

Hastings, et al. Standards Track [Page 144] RFC 2911 IPP/1.1: Model and Semantics September 2000

 A client MUST support Client Authentication as defined in the IPP/1.1
 Encoding and Transport document [RFC2910].  A client SHOULD support
 Operation Privacy and Server Authentication as defined in the IPP/1.1
 Encoding and Transport document [RFC2910].  See also section 8 of
 this document.

5.2 IPP Object Conformance Requirements

 This section specifies the conformance requirements for conforming
 implementations of IPP objects (see section 2).  These requirements
 apply to an IPP object whether it is:
    (1) an (embedded) device component that accepts IPP requests and
    controls the device or
    (2) a component of a print server that accepts IPP requests (where
    the print server control one or more networked devices using IPP or
    other protocols).

5.2.1 Objects

 Conforming implementations MUST implement all of the model objects as
 defined in this document in the indicated sections:
    Section 2.1 - Printer Object
    Section 2.2 - Job Object

5.2.2 Operations

 Conforming IPP object implementations MUST implement all of the
 REQUIRED model operations, including REQUIRED responses, as defined
 in this document in the indicated sections:
    For a Printer object:
       Print-Job (section 3.2.1)               REQUIRED
       Print-URI (section 3.2.2)               OPTIONAL
       Validate-Job (section 3.2.3)            REQUIRED
       Create-Job (section 3.2.4)              OPTIONAL
       Get-Printer-Attributes (section 3.2.5)  REQUIRED
       Get-Jobs (section 3.2.6)                REQUIRED
       Pause-Printer (section 3.2.7)           OPTIONAL
       Resume-Printer (section 3.2.8)          OPTIONAL
       Purge-Jobs (section 3.2.9)              OPTIONAL

Hastings, et al. Standards Track [Page 145] RFC 2911 IPP/1.1: Model and Semantics September 2000

    For a Job object:
       Send-Document (section 3.3.1)           OPTIONAL
       Send-URI (section 3.3.2)                OPTIONAL
       Cancel-Job (section 3.3.3)              REQUIRED
       Get-Job-Attributes (section 3.3.4)      REQUIRED
       Hold-Job (section 3.3.5)                OPTIONAL
       Release-Job (section 3.3.6)             OPTIONAL
       Restart-Job (section 3.3.7)             OPTIONAL
 Conforming IPP objects MUST support all REQUIRED operation attributes
 and all values of such attributes if so indicated in the description.
 Conforming IPP objects MUST ignore all unsupported or unknown
 operation attributes or operation attribute groups received in a
 request, but MUST reject a request that contains a supported
 operation attribute that contains an unsupported value.
 Conforming IPP objects MAY return operation responses that contain
 attributes groups, attributes names,  attribute syntaxes, attribute
 values, and status codes that are extensions to this standard.  The
 additional attribute groups MAY occur in any order.
 The following section on object attributes specifies the support
 required for object attributes.

5.2.3 IPP Object Attributes

 Conforming IPP objects MUST support all of the REQUIRED object
 attributes, as defined in this document in the indicated sections.
 If an object supports an attribute, it MUST support only those values
 specified in this document or through the extension mechanism
 described in section 5.2.4. It MAY support any non-empty subset of
 these values.  That is, it MUST support at least one of the specified
 values and at most all of them.

5.2.4 Versions

 IPP/1.1 clients MUST meet the conformance requirements for clients
 specified in this document and [RFC2910].  IPP/1.1 clients MUST send
 requests containing a "version-number" parameter with a '1.1' value.
 IPP/1.1 Printer and Job objects MUST meet the conformance
 requirements for IPP objects specified in this document and
 [RFC2910].   IPP/1.1 objects MUST accept requests containing a
 "version-number" parameter with a '1.1' value (or reject the request
 if the operation is not supported).

Hastings, et al. Standards Track [Page 146] RFC 2911 IPP/1.1: Model and Semantics September 2000

 It is beyond the scope of this specification to mandate conformance
 with previous versions.  IPP/1.1 was deliberately designed, however,
 to make supporting previous versions easy.  It is worth noting that,
 at the time of composing this specification (1999), we would expect
 IPP/1.1 Printer implementations to:
   understand any valid request in the format of IPP/1.0, or 1.1;
   respond appropriately with a response containing the same
   "version-number" parameter value used by the client in the request.
 And we would expect IPP/1.1 clients to:
   understand any valid response in the format of IPP/1.0, or 1.1.
 It is recommended that IPP/1.1 clients try supplying alternate
 version numbers if they receive a 'server-error-version-not-
 supported' error return in a response.

5.2.5 Extensions

 A conforming IPP object MAY support IETF standards track extensions
 and vendor extensions, as long as the extensions meet the
 requirements specified in Section 6.
 For each attribute included in an operation response, a conforming
 IPP object MUST return a value whose type and value syntax conforms
 to the requirement of the Model document as specified in Sections 3
 and 4.

5.2.6 Attribute Syntaxes

 An IPP object MUST be able to accept any of the attribute syntaxes
 defined in Section 4.1, including their full range, in any operation
 in which a client may supply attributes or the system administrator
 may configure attributes (by means outside the scope of this IPP/1.1
 document).  In particular for each attribute that the IPP object
 supports whose attribute syntax is 'text', the IPP object MUST accept
 and process both the 'textWithoutLanguage' and 'textWithLanguage'
 forms.  Similarly, for each attribute that the IPP object supports
 whose attribute syntax is 'name', the IPP object MUST accept and
 process both the 'nameWithoutLanguage' and 'nameWithLanguage' forms.
 Furthermore, an IPP object MUST return attributes to the client in
 operation responses that conform to the syntax specified in Section
 4.1, including their full range if supplied previously by a client.

Hastings, et al. Standards Track [Page 147] RFC 2911 IPP/1.1: Model and Semantics September 2000

5.2.7 Security

 An IPP Printer implementation SHOULD contain support for Client
 Authentication as defined in the IPP/1.1 Encoding and Transport
 document [RFC2910].  A Printer implementation MAY allow an
 administrator to configure the Printer so that all, some, or none of
 the users are authenticated.  See also section 8 of this document.
 An IPP Printer implementation SHOULD contain support for Operation
 Privacy and Server Authentication as defined in the IPP/1.1 Encoding
 and Transport document [RFC2910].  A Printer implementation MAY allow
 an administrator to configure the degree of support for Operation
 Privacy and Server Authentication.  See also section 8 of this
 document.
 Security MUST NOT be compromised when a client supplies a lower
 "version-number" parameter in a request.  For example, if an IPP/1.1
 conforming Printer object accepts version '1.0' requests and is
 configured to enforce Digest Authentication, it MUST do the same for
 a version '1.0' request.

5.3 Charset and Natural Language Requirements

 All clients and IPP objects MUST support the 'utf-8' charset as
 defined in section 4.1.7.
 IPP objects MUST be able to accept any client request which correctly
 uses the "attributes-natural-language" operation attribute or the
 Natural Language Override mechanism on any individual attribute
 whether or not the natural language is supported by the IPP object.
 If an IPP object supports a natural language, then it MUST be able to
 translate (perhaps by table lookup) all generated 'text' or 'name'
 attribute values into one of the supported languages (see section
 3.1.4).  That is, the IPP object that supports a natural language
 NEED NOT be a general purpose translator of any arbitrary 'text' or
 'name' value supplied by the client into that natural language.
 However, the object MUST be able to translate (automatically
 generate) any of its own attribute values and messages into that
 natural language.

6. IANA Considerations

 This section describes the procedures for defining semantics for the
 following IETF standards track extensions and vendor extensions to
 the IPP/1.1 Model and Semantics document:
    1. keyword attribute values
    2. enum attribute values

Hastings, et al. Standards Track [Page 148] RFC 2911 IPP/1.1: Model and Semantics September 2000

    3. attributes
    4. attribute syntaxes
    5. operations
    6. attribute groups
    7. status codes
    8. out-of-band attribute values
 Extensions registered for use with IPP/1.1 are OPTIONAL for client
 and IPP object conformance to the IPP/1.1 "Model and Semantics"
 document (this document).
 These extension procedures are aligned with the guidelines as set
 forth by the IESG [IANA-CON].  Section 11 describes how to propose
 new registrations for consideration.  IANA will reject registration
 proposals that leave out required information or do not follow the
 appropriate format described in Section 11.  The IPP/1.1 Model and
 Semantics document may also be extended by an appropriate RFC that
 specifies any of the above extensions.

6.1 Typed 'keyword' and 'enum' Extensions

 IPP allows for 'keyword' and 'enum' extensions (see sections 4.1.2.3
 and 4.1.4).  This document uses prefixes to the 'keyword' and 'enum'
 basic attribute syntax type in order to communicate extra information
 to the reader through its name. This extra information is not
 represented in the protocol because it is unimportant to a client or
 Printer object.  The list below describes the prefixes and their
 meaning.
    "type1":  This IPP specification document must be revised (or
       another IETF standards track document which augments this
       document) to add a new keyword or a new enum.  No vendor
       defined keywords or enums are allowed.
    "type2":  Implementers can, at any time, add new keyword or enum
       values by proposing the complete specification to IANA:
       iana@iana.org
       IANA will forward the registration proposal to the IPP
       Designated Expert who will review the proposal with a mailing
       list that the Designated Expert keeps for this purpose.
       Initially, that list will be the mailing list used by the IPP
       WG:
          ipp@pwg.org
       even after the IPP WG is disbanded as permitted by [IANA-CON].

Hastings, et al. Standards Track [Page 149] RFC 2911 IPP/1.1: Model and Semantics September 2000

       The IPP Designated Expert is appointed by the IESG Area
       Director responsible for IPP, according to [IANA-CON].
       When a type2 keyword or enum is approved, the IPP Designated
       Expert becomes the point of contact for any future maintenance
       that might be required for that registration.
    "type3":  Implementers can, at any time, add new keyword and enum
       values by submitting the complete specification to IANA as for
       type2 who will forward the proposal to the IPP Designated
       Expert.  While no additional technical review is required, the
       IPP Designated Expert may, at his/her discretion, forward the
       proposal to the same mailing list as for type2 registrations
       for advice and comment.
       When a type3 keyword or enum is approved by the IPP Designated
       Expert, the original proposer becomes the point of contact for
       any future maintenance that might be required for that
       registration.
 For type2 and type3 keywords, the proposer includes the name of the
 keyword in the registration proposal and the name is part of the
 technical review.
 After type2 and type3 enums specifications are approved, the IPP
 Designated Expert in consultation with IANA assigns the next
 available enum number for each enum value.
 IANA will publish approved type2 and type3 keyword and enum
 attributes value registration specifications in:
    ftp.isi.edu/iana/assignments/ipp/attribute-values/xxx/yyy.txt
 where xxx is the attribute name that specifies the initial values and
 yyy.txt is a descriptive file name that contains one or more enums or
 keywords approved at the same time.  For example, if several
 additional enums for stapling are approved for use with the
 "finishings" attribute (and "finishings-default" and "finishings-
 supported" attributes), IANA will publish the additional values in
 the file:
    ftp.isi.edu/iana/assignments/ipp/attribute-
    values/finishings/stapling.txt
 Note: Some attributes are defined to be: 'type3 keywords' | 'name'
 which allows for attribute values to be extended by a site
 administrator with administrator defined names.  Such names are not
 registered with IANA.

Hastings, et al. Standards Track [Page 150] RFC 2911 IPP/1.1: Model and Semantics September 2000

 By definition, each of the three types above assert some sort of
 registry or review process in order for extensions to be considered
 valid.  Each higher numbered level (1, 2, 3) tends to be decreasingly
 less stringent than the previous level.   Therefore, any typeN value
 MAY be registered using a process for some typeM where M is less than
 N, however such registration is NOT REQUIRED.  For example, a type3
 value MAY be registered in a type 1 manner (by being included in a
 future version of an IPP specification), however, it is NOT REQUIRED.
 This document defines keyword and enum values for all of the above
 types, including type3 keywords.
 For vendor keyword extensions, implementers SHOULD use keywords with
 a suitable distinguishing prefix, such as "xxx-" where xxx follows
 the syntax rules for keywords (see section 4.1.3) and is the
 (lowercase) fully qualified company name registered with IANA for use
 in domain names [RFC1035].  For example, if the company XYZ Corp. had
 obtained the domain name "XYZ.com", then a vendor keyword 'abc' would
 be: 'xyz.com-abc'.
 Note: RFC 1035 [RFC1035] indicates that while upper and lower case
 letters are allowed in domain names, no significance is attached to
 the case.  That is, two names with the same spelling but different
 case are to be treated as if identical.  Also, the labels in a domain
 name must follow the rules for ARPANET host names:  They must start
 with a letter, end with a letter or digit, and have as interior
 characters only letters, digits, and hyphen.  Labels must be 63
 characters or less.  Labels are separated by the "." character.
 For vendor enum extensions, implementers MUST use values in the
 reserved integer range which is 2**30 to 2**31-1.

6.2 Attribute Extensibility

 Attribute names (see section 4.1.3) are type2 keywords.  Therefore,
 new attributes may be registered and have the same status as
 attributes in this document by following the type2 extension rules.
 For vendor attribute extensions, implementers SHOULD use keywords
 with a suitable distinguishing prefix as described in Section 6.1.
 IANA will publish approved attribute registration specifications as
 separate files:
    ftp.isi.edu/iana/assignments/ipp/attributes/xxx-yyy.txt
 where "xxx-yyy" is the new attribute name.

Hastings, et al. Standards Track [Page 151] RFC 2911 IPP/1.1: Model and Semantics September 2000

 If a new Printer object attribute is defined and its values can be
 affected by a specific document format, its specification needs to
 contain the following sentence:
       "The value of this attribute returned in a Get-Printer-
       Attributes response MAY depend on the "document-format"
       attribute supplied (see Section 3.2.5.1)."
 If the specification does not, then its value in the Get-Printer-
 Attributes response MUST NOT depend on the "document-format" supplied
 in the request.  When a new Job Template attribute is registered, the
 value of the Printer attributes MAY vary with "document-format"
 supplied in the request without the specification having to indicate
 so.

6.3 Attribute Syntax Extensibility

 Attribute syntaxes (see section 4.1) are like type2 enums.
 Therefore, new attribute syntaxes may be registered and have the same
 status as attribute syntaxes in this document by following the type2
 extension rules described in Section 6.1.  The initial set of value
 codes that identify each of the attribute syntaxes have been assigned
 in the "Encoding and Transport" document [RFC2910], including a
 designated range for vendor extension.
 For attribute syntaxes, the IPP Designated Expert in consultation
 with IANA assigns the next attribute syntax code in the appropriate
 range as specified in [RFC2910].  IANA will publish approved
 attribute syntax registration specifications as separate files:
    ftp.isi.edu/iana/assignments/ipp/attribute-syntaxes/xxx-yyy.txt
 where 'xxx-yyy' is the new attribute syntax name.

6.4 Operation Extensibility

 Operations (see section 3) may also be registered following the type2
 procedures described in Section 6.1, though major new operations will
 usually be done by a new standards track RFC that augments this
 document.  For vendor operation extensions, implementers MUST use the
 range for the "operation-id" in requests specified in Section 4.4.15
 "operations-supported" Printer attribute.
 For operations, the IPP Designated Expert in consultation with IANA
 assigns the next operation-id code as specified in Section 4.4.15.
 IANA will publish approved operation registration specifications as
 separate files:

Hastings, et al. Standards Track [Page 152] RFC 2911 IPP/1.1: Model and Semantics September 2000

    ftp.isi.edu/iana/assignments/ipp/operations/Xxx-Yyy.txt
 where "Xxx-Yyy" is the new operation name.

6.5 Attribute Group Extensibility

 Attribute groups (see section 3.1.3) passed in requests and responses
 may be registered following the type2 procedures described in Section
 6.1.  The initial set of attribute group tags have been assigned in
 the "Encoding and Transport" document [RFC2910], including a
 designated range for vendor extension.
 For attribute groups, the IPP Designated Expert in consultation with
 IANA assigns the next attribute group tag code in the appropriate
 range as specified in [RFC2910].  IANA will publish approved
 attribute group registration specifications as separate files:
    ftp.isi.edu/iana/assignments/ipp/attribute-group-tags/xxx-yyy-
    tag.txt
 where 'xxx-yyy-tag' is the new attribute group tag name.

6.6 Status Code Extensibility

 Operation status codes (see section 3.1.6.1) may also be registered
 following the type2 procedures described in Section 6.1.  The values
 for status codes are allocated in ranges as specified in Section 14
 for each status code class:
    "informational" - Request received, continuing process
    "successful" - The action was successfully received, understood, and
       accepted
    "redirection" - Further action must be taken in order to complete the
       request
    "client-error" - The request contains bad syntax or cannot be
       fulfilled
    "server-error" - The IPP object  failed to fulfill an apparently
       valid request
 For vendor operation status code extensions, implementers MUST use
 the top of each range as specified in Section 13.
 For operation status codes, the IPP Designated Expert in consultation
 with IANA assigns the next status code in the appropriate class range
 as specified in Section 13.  IANA will publish approved status code
 registration specifications as separate files:
    ftp.isi.edu/iana/assignments/ipp/status-codes/xxx-yyy.txt

Hastings, et al. Standards Track [Page 153] RFC 2911 IPP/1.1: Model and Semantics September 2000

 where "xxx-yyy" is the new operation status code keyword.

6.7 Out-of-band Attribute Value Extensibility

 Out-of-band attribute values (see the beginning of section 4.1)
 passed in requests and responses may be registered following the
 type2 procedures described in Section 6.1.  The initial set of out-
 of-band attribute value tags have been assigned in the "Encoding and
 Transport" document [RFC2910].
 For out-of-band attribute value tags, the IPP Designated Expert in
 consultation with IANA assigns the next out-of-band attribute value
 tag code in the appropriate range as specified in [RFC2910].  IANA
 will publish approved out-of-band attribute value tags registration
 specifications as separate files:
    ftp.isi.edu/iana/assignments/ipp/out-of-band-attribute-value-
    tags/xxx-yyy-tag.txt
 where 'xxx-yyy-tag' is the new out-of-band attribute value tag name.

6.8 Registration of MIME types/sub-types for document-formats

 The "document-format" attribute's syntax is 'mimeMediaType'.  This
 means that valid values are Internet Media Types (see Section 4.1.9).
 RFC 2045 [RFC2045] defines the syntax for valid Internet media types.
 IANA is the registry for all Internet media types.

6.9 Registration of charsets for use in 'charset' attribute values

 The "attributes-charset" attribute's syntax is 'charset'.  This means
 that valid values are charsets names.  When a charset in the IANA
 registry has more than one name (alias), the name labeled as
 "(preferred MIME name)", if present, MUST be used (see Section
 4.1.7).  IANA is the registry for charsets following the procedures
 of [RFC2278].

7. Internationalization Considerations

 Some of the attributes have values that are text strings and names
 which are intended for human understanding rather than machine
 understanding (see the 'text' and 'name' attribute syntaxes in
 Sections 4.1.1 and 4.1.2).
 In each operation request, the client
  1. identifies the charset and natural language of the request which

affects each supplied 'text' and 'name' attribute value, and

Hastings, et al. Standards Track [Page 154] RFC 2911 IPP/1.1: Model and Semantics September 2000

  1. requests the charset and natural language for attributes

returned by the IPP object in operation responses (as described

      in Section 3.1.4.1).
 In addition, the client MAY separately and individually identify the
 Natural Language Override of a supplied 'text' or 'name' attribute
 using the 'textWithLanguage' and 'nameWithLanguage' technique
 described section 4.1.1.2 and 4.1.2.2 respectively.
 All IPP objects MUST support the UTF-8 [RFC2279] charset in all
 'text' and 'name' attributes supported.  If an IPP object supports
 more than the UTF-8 charset, the object MUST convert between them in
 order to return the requested charset to the client according to
 Section 3.1.4.2.  If an IPP object supports more than one natural
 language, the object SHOULD return 'text' and 'name' values in the
 natural language requested where those values are generated by the
 Printer (see Section 3.1.4.1).
 For Printers that support multiple charsets and/or multiple natural
 languages in 'text' and 'name' attributes, different jobs may have
 been submitted in differing charsets and/or natural languages.  All
 responses MUST be returned in the charset requested by the client.
 However, the Get-Jobs operation uses the 'textWithLanguage' and
 'nameWithLanguage' mechanism to identify the differing natural
 languages with each job attribute returned.
 The Printer object also has configured charset and natural language
 attributes.   The client can query the Printer object to determine
 the list of charsets and natural languages supported by the Printer
 object and what the Printer object's configured values are.  See the
 "charset-configured", "charset-supported", "natural-language-
 configured", and "generated-natural-language-supported" Printer
 description attributes for more details.
 The "charset-supported" attributed identifies the supported charsets.
 If a charset is supported, the IPP object MUST be capable of
 converting to and from that charset into any other supported charset.
 In many cases, an IPP object will support only one charset and it
 MUST be the UTF-8 charset.
 The "charset-configured" attribute identifies the one supported
 charset which is the native charset given the current configuration
 of the IPP object (administrator defined).
 The "generated-natural-language-supported" attribute identifies the
 set of supported natural languages for generated messages; it is not
 related to the set of natural languages that must be accepted for
 client supplied 'text' and 'name' attributes.  For client supplied

Hastings, et al. Standards Track [Page 155] RFC 2911 IPP/1.1: Model and Semantics September 2000

 'text' and 'name' attributes, an IPP object MUST accept ALL supplied
 natural languages.  Just because a Printer object is currently
 configured to support 'en-us' natural language does not mean that the
 Printer object should reject a job if the client supplies a job name
 that is in 'fr-ca'.
 The "natural-language-configured" attribute identifies the one
 supported natural language for generated messages which is the native
 natural language given the current configuration of the IPP object
 (administrator defined).
 Attributes of type 'text' and 'name' are populated from different
 sources.  These attributes can be categorized into following groups
 (depending on the source of the attribute):
    1. Some attributes are supplied by the client (e.g., the client
       supplied "job-name", "document-name", and "requesting-user-
       name" operation attributes along with the corresponding Job
       object's "job-name" and "job-originating-user-name"
       attributes).  The IPP object MUST accept these attributes in
       any natural language no matter what the set of supported
       languages for generated messages
    2. Some attributes are supplied by the system administrator (e.g.,
       the Printer object's "printer-name" and "printer-location"
       attributes).  These too can be in any natural language.  If the
       natural language for these attributes is different than what a
       client requests, then they must be reported using the Natural
       Language Override mechanism.
    3. Some attributes are supplied by the device manufacturer (e.g.,
       the Printer object's "printer-make-and-model" attribute).
       These too can be in any natural language.  If the natural
       language for these attributes is different than what a client
       requests, then they must be reported using the Natural Language
       Override mechanism.
    4. Some attributes are supplied by the operator (e.g., the Job
       object's "job-message-from-operator" attribute). These too can
       be in any natural language.  If the natural language for these
       attributes is different than what a client requests, then they
       must be reported using the Natural Language Override mechanism.
    5. Some attributes are generated by the IPP object (e.g., the Job
       object's "job-state-message" attribute, the Printer object's
       "printer-state-message" attribute, and the "status-message"
       operation attribute).  These attributes can only be in one of
       the "generated-natural-language-supported" natural languages.
       If a client requests some natural language for these attributes
       other than one of the supported values, the IPP object SHOULD

Hastings, et al. Standards Track [Page 156] RFC 2911 IPP/1.1: Model and Semantics September 2000

       respond using the value of the "natural-language-configured"
       attribute (using the Natural Language Override mechanism if
       needed).
 The 'text' and 'name' attributes specified in this version of this
 document (additional ones will be registered according to the
 procedures in Section 6) are:
                  Attributes                            Source
 Operation Attributes:
      job-name (name)                         client
      document-name (name)                    client
      requesting-user-name (name)             client
      status-message (text)                   Job or Printer object
      detailed-status-message (text)          Job or Printer object -
                                              see rule 1
      document-access-error (text)            Job or Printer object -
                                              see rule 1
 Job Template Attributes:
      job-hold-until (keyword | name)         client matches
                                              administrator-configured
      job-hold-until-default (keyword | name) client matches
                                              administrator-configured
      job-hold-until-supported (keyword |     client matches
      name)                                   administrator-configured
      job-sheets (keyword | name)             client matches
                                              administrator-configured
      job-sheets-default (keyword | name)     client matches
                                              administrator-configured
      job-sheets-supported (keyword | name)   client matches
                                              administrator-configured
      media (keyword | name)                  client matches
                                              administrator-configured
      media-default (keyword | name)          client matches
                                              administrator-configured
      media-supported (keyword | name)        client matches
                                              administrator-configured
      media-ready (keyword | name)            client matches
                                              administrator-configured
 Job Description Attributes:
      job-name (name)                         client or Printer object
      job-originating-user-name (name)        Printer object
      job-state-message (text)                Job or Printer object
      output-device-assigned (name(127))      administrator
      job-message-from-operator (text(127))   operator

Hastings, et al. Standards Track [Page 157] RFC 2911 IPP/1.1: Model and Semantics September 2000

      job-detailed-status-messages (1setOf    Job or Printer object -
      text)                                   see rule 1
      job-document-access-errors (1setOf      Job or Printer object -
      text)                                   see rule 1
 Printer Description Attributes:
      printer-name (name(127))                administrator
      printer-location (text(127))            administrator
      printer-info (text(127))                administrator
      printer-make-and-model (text(127))      administrator or
                                              manufacturer
      printer-state-message (text)            Printer object
      printer-message-from-operator           operator
      (text(127))
 Rule 1 - Neither the Printer nor the client localizes these message
 attributes, since they are intended for use by the system
 administrator or other experienced technical persons.

8. Security Considerations

 It is difficult to anticipate the security risks that might exist in
 any given IPP environment. For example, if IPP is used within a given
 corporation over a private network, the risks of exposing document
 data may be low enough that the corporation will choose not to use
 encryption on that data.  However, if the connection between the
 client and the IPP object is over a public network, the client may
 wish to protect the content of the information during transmission
 through the network with encryption.
 Furthermore, the value of the information being printed may vary from
 one IPP environment to the next. Printing payroll checks, for
 example, would have a different value than printing public
 information from a file.  There is also the possibly of denial-of-
 service attacks, but denial-of-service attacks against printing
 resources are not well understood and there is no published
 precedents regarding this scenario.
 Once the authenticated identity of the requester has been supplied to
 the IPP object, the object uses that identity to enforce any
 authorization policy that might be in place.  For example, one site's
 policy might be that only the job owner is allowed to cancel a job.
 The details and mechanisms to set up a particular access control
 policy are not part of IPP/1.1, and must be established via some
 other type of administrative or access control framework.  However,
 there are operation status codes that allow an IPP server to return
 information back to a client about any potential access control
 violations for an IPP object.

Hastings, et al. Standards Track [Page 158] RFC 2911 IPP/1.1: Model and Semantics September 2000

 During a create operation, the client's identity is recorded in the
 Job object in an implementation-defined attribute.  This information
 can be used to verify a client's identity for subsequent operations
 on that Job object in order to enforce any access control policy that
 might be in effect.  See section 8.3 below for more details.
 Since the security levels or the specific threats that an IPP system
 administrator may be concerned with cannot be anticipated, IPP MUST
 be capable of operating with different security mechanisms and
 security policies as required by the individual installation.
 Security policies might vary from very strong, to very weak, to none
 at all, and corresponding security mechanisms will be required.

8.1 Security Scenarios

 The following sections describe specific security attacks for IPP
 environments.  Where examples are provided they should be considered
 illustrative of the environment and not an exhaustive set. Not all of
 these environments will necessarily be addressed in initial
 implementations of IPP.

8.1.1 Client and Server in the Same Security Domain

 This environment is typical of internal networks where traditional
 office workers print the output of personal productivity applications
 on shared work-group printers, or where batch applications print
 their output on large production printers. Although the identity of
 the user may be trusted in this environment, a user might want to
 protect the content of a document against such attacks as
 eavesdropping, replaying or tampering.

8.1.2 Client and Server in Different Security Domains

 Examples of this environment include printing a document created by
 the client on a publicly available printer, such as at a commercial
 print shop; or printing a document remotely on a business associate's
 printer.  This latter operation is functionally equivalent to sending
 the document to the business associate as a facsimile. Printing
 sensitive information on a Printer in a different security domain
 requires strong security measures. In this environment authentication
 of the printer is required as well as protection against unauthorized
 use of print resources. Since the document crosses security domains,
 protection against eavesdropping and document tampering are also
 required. It will also be important in this environment to protect
 Printers against "spamming" and malicious document content.

Hastings, et al. Standards Track [Page 159] RFC 2911 IPP/1.1: Model and Semantics September 2000

8.1.3 Print by Reference

 When the document is not stored on the client, printing can be done
 by reference. That is, the print request can contain a reference, or
 pointer, to the document instead of the actual document itself (see
 sections 3.2.2 and 3.3.2). Standard methods currently do not exist
 for remote entities to "assume" the credentials of a client for
 forwarding requests to a 3rd party. It is anticipated that Print-By-
 Reference will be used to access "public" documents and that
 sophisticated methods for authenticating "proxies" is not specified
 in this document.

8.2 URIs in Operation, Job, and Printer attributes

 The "printer-uri-supported" attribute contains the Printer object's
 URI(s).  Its companion attribute, "uri-security-supported",
 identifies the security mechanism used for each URI listed in the
 "printer-uri-supported" attribute.  For each Printer operation
 request, a client MUST supply only one URI in the "printer-uri"
 operation attribute.  In other words, even though the Printer
 supports more than one URI, the client only interacts with the
 Printer object using one if its URIs.  This duality is not needed for
 Job objects, since the Printer objects is the factory for Job
 objects, and the Printer object will generate the correct URI for new
 Job objects depending on the Printer object's security configuration.

8.3 URIs for each authentication mechanisms

 Each URI has an authentication mechanism associated with it. If the
 URI is the i'th element of "printer-uri-supported", then
 authentication mechanism is the "i th" element of "uri-
 authentication-supported". For a list of possible authentication
 mechanisms, see section 4.4.2.
 The Printer object uses an authentication mechanism to determine the
 name of the user performing an operation. This user is called the
 "authenticated user". The credibility of authentication depends on
 the mechanism that the Printer uses to obtain the user's name. When
 the authentication mechanism is 'none', all authenticated users are
 "anonymous".
 During job creation operations, the Printer initializes the value of
 the "job-originating-user-name" attribute (see section 4.3.6) to be
 the authenticated user. The authenticated user is this case is called
 the "job owner".

Hastings, et al. Standards Track [Page 160] RFC 2911 IPP/1.1: Model and Semantics September 2000

 If an implementation can be configured to support more than one
 authentication mechanism (see section 4.4.2), then it MUST implement
 rules for determining equality of authenticated user names which have
 been authenticated via different authentication mechanisms.  One
 possible policy is that identical names that are authenticated via
 different mechanisms are different.  For example, a user can cancel
 his job only if he uses the same authentication mechanism for both
 Cancel-Job and Print-Job.  Another policy is that identical names
 that are authenticated via different mechanism are the same if the
 authentication mechanism for the later operation is not less strong
 than the authentication mechanism for the earlier job creation
 operation.  For example, a user can cancel his job only if he uses
 the same or stronger authentication mechanism for Cancel-Job and
 Print-Job. With this second policy a job submitted via 'requesting-
 user-name' authentication could be canceled via 'digest'
 authentication. With the first policy, the job could not be canceled
 in this way.
 A client is able to determine the authentication mechanism used to
 create a job. It is the i'th value of the Printer's "uri-
 authentication-supported" attribute (see section 4.4.2), where i is
 the index of the element of the Printer's "printer-uri-supported"
 attribute (see section 4.4.1) equal to the job's "job-printer-uri"
 attribute (see section 4.3.3).

8.4 Restricted Queries

 In many IPP operations, a client supplies a list of attributes to be
 returned in the response.  For security reasons, an IPP object may be
 configured not to return all attributes (or all values) that a client
 requests.  The job attributes returned MAY depend on whether the
 requesting user is the same as the user that submitted the job. The
 IPP object MAY even return none of the requested attributes. In such
 cases, the status returned is the same as if the object had returned
 all requested attributes.  The client cannot tell by such a response
 whether the requested attribute was present or absent on the object.

8.5 Operations performed by operators and system administrators

 For the three printer operations Pause-Printer, Resume-Printer, and
 Purge-Jobs (see sections 3.2.7, 3.2.8 and 3.2.9), the requesting user
 is intended to be an operator or administrator of the Printer object
 (see section 1).  Otherwise, the IPP Printer MUST reject the
 operation and return:  'client-error-forbidden', 'client-error-not-
 authenticated', or 'client-error-not-authorized' as appropriate.  For
 operations on jobs, the requesting user is intended to be the job

Hastings, et al. Standards Track [Page 161] RFC 2911 IPP/1.1: Model and Semantics September 2000

 owner or may be an operator or administrator of the Printer object.
 The means for authorizing an operator or administrator of the Printer
 object are not specified in this document.

8.6 Queries on jobs submitted using non-IPP protocols

 If the device that an IPP Printer is representing is able to accept
 jobs using other job submission protocols in addition to IPP, it is
 RECOMMENDED that such an implementation at least allow such "foreign"
 jobs to be queried using Get-Jobs returning "job-id" and "job-uri" as
 'unknown'.  Such an implementation NEED NOT support all of the same
 IPP job attributes as for IPP jobs.  The IPP object returns the
 'unknown' out-of-band value for any requested attribute of a foreign
 job that is supported for IPP jobs, but not for foreign jobs.
 It is further RECOMMENDED, that the IPP Printer generate "job-id" and
 "job-uri" values for such "foreign jobs", if possible, so that they
 may be targets of other IPP operations, such as Get-Job-Attributes
 and Cancel-Job.  Such an implementation also needs to deal with the
 problem of authentication of such foreign jobs.  One approach would
 be to treat all such foreign jobs as belonging to users other than
 the user of the IPP client.  Another approach would be for the
 foreign job to belong to 'anonymous'.  Only if the IPP client has
 been authenticated as an operator or administrator of the IPP Printer
 object, could the foreign jobs be queried by an IPP request.
 Alternatively, if the security policy is to allow users to query
 other users' jobs, then the foreign jobs would also be visible to an
 end-user IPP client using Get-Jobs and Get-Job-Attributes.

9. References

 [ASME-Y14.1M] Metric Drawing Sheet Size and Format, ASME Y14.1M-1995.
               This standard defines metric sheet sizes and formats
               for engineering drawings.
 [ASCII]       Coded Character Set - 7-bit American Standard Code for
               Information Interchange (ASCII), ANSI X3.4-1986. This
               standard is the specification of the US-ASCII charset.
 [BCP-11]      Bradner S. and R. Hovey, "The Organizations Involved in
               the IETF Standards Process", BCP 11, RFC 2028, October
               1996.
 [HTPP]        J. Barnett, K. Carter, R. DeBry,  "Initial Draft -
               Hypertext Printing Protocol - HTPP/1.0", October 1996,
            ftp://ftp.pwg.org/pub/pwg/ipp/historic/htpp/overview.ps.gz

Hastings, et al. Standards Track [Page 162] RFC 2911 IPP/1.1: Model and Semantics September 2000

 [IANA-CON]    Narten, T. and H. Alvestrand, "Guidelines for Writing
               an IANA Considerations Section in RFCs", BCP 26, RFC
               2434, October 1998.
 [IANA-CS]     IANA Registry of Coded Character Sets:
               ftp://ftp.isi.edu/in-notes/iana/assignments/character-
               sets
 [IANA-MT]     IANA Registry of Media Types:  ftp://ftp.isi.edu/in-
               notes/iana/assignments/media-types/
 [IPP-IIG]     Hastings, T., Manros, C., Kugler, C., Holst, H., and P.
               Zehler, "Internet Printing Protocol/1.1:  draft-ietf-
               ipp-implementers-guide-v11-01.txt, work in progress,
               May 30, 2000.
 [ISO10646-1]  ISO/IEC 10646-1:1993, "Information technology --
               Universal Multiple-Octet Coded Character Set (UCS) -
               Part 1: Architecture and Basic Multilingual Plane,
               JTC1/SC2."
 [ISO8859-1]   ISO/IEC 8859-1:1987, "Information technology -- 8-bit
               One-Byte Coded Character Set - Part 1: Latin Alphabet
               Nr 1", 1987, JTC1/SC2.
 [ISO10175]    ISO/IEC 10175 Document Printing Application (DPA), June
               1996.
 [LDPA]        T. Hastings,  S. Isaacson,  M. MacKay, C. Manros, D.
               Taylor, P. Zehler,  "LDPA - Lightweight Document
               Printing Application", October 1996,
            ftp://ftp.pwg.org/pub/pwg/ipp/historic/ldpa/ldpa8.pdf.gz
 [P1387.4]     Kirk, M. (editor), POSIX System Administration - Part
               4:  Printing Interfaces, POSIX 1387.4 D8, 1994.
 [PSIS]        Herriot, R. (editor), X/Open A Printing System
               Interoperability Specification (PSIS), August 1995.
 [PWG]         Printer Working Group, http://www.pwg.org.
 [RFC1035]     Mockapetris, P., "Domain Names - Implementation and
               Specification", STD 13, RFC 1035, November 1987.
 [RFC1179]     McLaughlin, L., "Line Printer Daemon Protocol", RFC
               1179, August 1990.

Hastings, et al. Standards Track [Page 163] RFC 2911 IPP/1.1: Model and Semantics September 2000

 [RFC1759]     Smith, R., Wright, F., Hastings, T., Zilles, S. and J.
               Gyllenskog, "Printer MIB", RFC 1759, March 1995.
 [RFC1766]     Alvestrand, H., "Tags for the Identification of
               Languages", RFC 1766, March 1995.
 [RFC1951]     Deutsch, P., "DEFLATE Compressed Data Format
               Specification version 1.3 ", RFC 1951, May 1996.
 [RFC1952]     Deutsch, P., "GZIP file format specification version
               4.3", RFC 1952, May 1996.
 [RFC1977]     Schryver, V., "PPP BSD Compression Protocol", RFC 1977,
               August 1996.
 [RFC2026]     Bradner, S., "The Internet Standards Process --
               Revision 3", BCP 9, RFC 2026, October 1996.
 [RFC2045]     Freed, N. and  N. Borenstein, ", Multipurpose Internet
               Mail Extensions (MIME) Part One: Format of Internet
               Message Bodies", RFC 2045, November 1996.
 [RFC2046]     Freed, N. and N. Borenstein, "Multipurpose Internet
               Mail Extensions (MIME) Part Two: Media Types", RFC
               2046, November 1996.
 [RFC2048]     Freed, N., Klensin, J. and J. Postel, "Multipurpose
               Internet Mail Extension (MIME) Part Four: Registration
               Procedures", RFC 2048, November 1996.
 [RFC2119]     Bradner, S., "Key words for use in RFCs to Indicate
               Requirement Levels", BCP 14, RFC 2119, March 1997.
 [RFC2228]     Horowitz, M. and S. Lunt, "FTP Security Extensions",
               RFC 2228, October 1997.
 [RFC2246]     Dierks, T. and C. Allen, "The TLS Protocol Version
               1.0", RFC 2246, January 1999.
 [RFC2277]     Alvestrand, H., "IETF Policy on Character Sets and
               Languages" BCP 18, RFC 2277, January 1998.
 [RFC2278]     Freed, N. and J. Postel: "IANA CharSet Registration
               Procedures", BCP 19, RFC 2278, January 1998.
 [RFC2279]     Yergeau, F., "UTF-8, a transformation format of ISO
               10646", RFC 2279, January 1998.

Hastings, et al. Standards Track [Page 164] RFC 2911 IPP/1.1: Model and Semantics September 2000

 [RFC2316]     Bellovin, S., "Report of the IAB Security Architecture
               Workshop", RFC 2316, April 1998.
 [RFC2396]     Berners-Lee, T., Fielding, R. and L. Masinter, "Uniform
               Resource Identifiers (URI): Generic Syntax", RFC 2396,
               August 1998.
 [RFC2565]     Herriot, R., Butler, S., Moore, P. and R. Turner,
               "Internet Printing Protocol/1.0: Encoding and
               Transport", RFC 2565, April 1999.
 [RFC2566]     deBry, R., Hastings, T., Herriot, R., Isaacson, S. and
               P. Powell, "Internet Printing Protocol/1.0: Model and
               Semantics", RFC 2566, April 1999.
 [RFC2567]     Wright, D., "Design Goals for an Internet Printing
               Protocol", RFC 2567, April 1999.
 [RFC2568]     Zilles, S., "Rationale for the Structure and Model and
               Protocol for the Internet Printing Protocol", RFC 2568,
               April 1999.
 [RFC2569]     Herriot, R., Hastings, T., Jacobs, N. and J. Martin,
               "Mapping between LPD and IPP Protocols", RFC 2569,
               April 1999.
 [RFC2579]     McCloghrie, K., Perkins, D. and J. Schoenwaelder,
               "Textual Conventions for SMIv2", STD 58, RFC 2579,
               April 1999.
 [RFC2616]     Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
               Masinter, L., Leach, P. and T. Berners-Lee, "Hypertext
               Transfer Protocol - HTTP/1.1", RFC 2616, June 1999.
 [RFC2617]     Franks, J., Hallam-Baker, P., Hostetler, J., Lawrence,
               S., Leach, P., Luotonen, A. and L. Stewart, "HTTP
               Authentication:  Basic and Digest Access
               Authentication", RFC 2617, June 1999.
 [RFC2639]     Hastings, T. and C. Manros, "Internet Printing
               Protocol/1.0: Encoding and Transport", RFC 2639, July
               1999.
 [RFC2910]     Herriot, R., Butler, S., Moore, P., Turner, R. and J.
               Wenn, "Internet Printing Protocol/1.1: Encoding and
               Transport", RFC 2910, September 2000.

Hastings, et al. Standards Track [Page 165] RFC 2911 IPP/1.1: Model and Semantics September 2000

 [SSL]         Netscape, The SSL Protocol, Version 3, (Text version
               3.02), November 1996.
 [SWP]         P. Moore, B. Jahromi, S. Butler, "Simple Web Printing
               SWP/1.0", May 7, 1997,
               ftp://ftp.pwg.org/pub/pwg/ipp/new_PRO/swp9705.pdf

10. Authors' Addresses

 Scott A. Isaacson, Editor
 Novell, Inc.
 122 E 1700 S
 Provo, UT   84606
 Phone: 801-861-7366
 Fax:   801-861-2517
 EMail: sisaacson@novell.com
 Tom Hastings
 Xerox Corporation
 737 Hawaii St.  ESAE 231
 El Segundo, CA   90245
 Phone: 310-333-6413
 Fax:   310-333-5514
 EMail: hastings@cp10.es.xerox.com
 Robert Herriot
 Xerox Corp.
 3400 Hill View Ave, Building 1
 Palo Alto, CA 94304
 Phone: 650-813-7696
 Fax:  650-813-6860
 EMail: robert.herriot@pahv.xerox.com
 Roger deBry
 Utah Valley State College
 Orem, UT 84058
 Phone: (801) 222-8000
 EMail: debryro@uvsc.edu

Hastings, et al. Standards Track [Page 166] RFC 2911 IPP/1.1: Model and Semantics September 2000

 Patrick Powell
 Astart Technologies
 9475 Chesapeake Dr., Suite D
 San Diego, CA  95123
 Phone: (619) 874-6543
 Fax:   (619) 279-8424
 EMail: papowell@astart.com
 IPP Web Page:  http://www.pwg.org/ipp/
 IPP Mailing List:  ipp@pwg.org
 To subscribe to the ipp mailing list, send the following email:
    1) send it to majordomo@pwg.org
    2) leave the subject line blank
    3) put the following two lines in the message body:
          subscribe ipp
          end
 Implementers of this specification document are encouraged to join
 IPP Mailing List in order to participate in any discussions of
 clarification issues and review of registration proposals for
 additional attributes and values.
 Other Participants:
 Chuck Adams - Tektronix             Shivaun Albright - HP
 Stefan Andersson - Axis             Jeff Barnett - IBM
 Ron Bergman - Hitachi Koki Imaging  Dennis Carney - IBM
 Systems
 Keith Carter - IBM                  Angelo Caruso - Xerox
 Rajesh Chawla - TR Computing        Nancy Chen - Okidata
 Solutions
 Josh Cohen - Microsoft              Jeff Copeland - QMS
 Andy Davidson - Tektronix           Roger deBry - IBM
 Maulik Desai - Auco                 Mabry Dozier - QMS
 Lee Farrell - Canon Information     Satoshi Fujitami - Ricoh
 Systems
 Steve Gebert - IBM                  Sue Gleeson - Digital
 Charles Gordon - Osicom             Brian Grimshaw - Apple
 Jerry Hadsell - IBM                 Richard Hart - Digital
 Tom Hastings - Xerox                Henrik Holst - I-data
 Stephen Holmstead                   Zhi-Hong Huang - Zenographics
 Scott Isaacson - Novell             Babek Jahromi - Microsoft
 Swen Johnson - Xerox                David Kellerman - Northlake
                                     Software
 Robert Kline - TrueSpectra          Charles Kong - Panasonic
 Carl Kugler - IBM                   Dave Kuntz - Hewlett-Packard

Hastings, et al. Standards Track [Page 167] RFC 2911 IPP/1.1: Model and Semantics September 2000

 Takami Kurono - Brother             Rick Landau - Digital
 Scott Lawrence - Agranot Systems    Greg LeClair - Epson
 Dwight Lewis - Lexmark              Harry Lewis - IBM
 Tony Liao - Vivid Image             Roy Lomicka - Digital
 Pete Loya - HP                      Ray Lutz - Cognisys
 Mike MacKay - Novell, Inc.          David Manchala - Xerox
 Carl-Uno Manros - Xerox             Jay Martin - Underscore
 Stan McConnell - Xerox              Larry Masinter - Xerox
 Sandra Matts - Hewlett Packard      Peter Michalek - Shinesoft
 Ira McDonald - High North Inc.      Mike Moldovan - G3 Nova
 Tetsuya Morita - Ricoh              Yuichi Niwa - Ricoh
 Pat Nogay - IBM                     Ron Norton - Printronics
 Hugo Parra, Novell                  Bob Pentecost - Hewlett-Packard
 Patrick Powell - Astart             Jeff Rackowitz - Intermec
 Technologies
 Eric Random - Peerless              Rob Rhoads - Intel
 Xavier Riley - Xerox                Gary Roberts - Ricoh
 David Roach - Unisys                Stuart Rowley - Kyocera
 Yuji Sasaki - Japan Computer        Richard Schneider - Epson
 Industry
 Kris Schoff - HP                    Katsuaki Sekiguchi - Canon
 Bob Setterbo - Adobe                Gail Songer - Peerless
 Hideki Tanaka - Cannon              Devon Taylor - Novell
 Mike Timperman - Lexmark            Atsushi Uchino - Epson
 Shigeru Ueda - Canon                Bob Von Andel - Allegro Software
 William Wagner - NetSilicon/DPI     Jim Walker - DAZEL
 Chris Wellens - Interworking Labs   Trevor Wells - Hewlett Packard
 Craig Whittle - Sharp Labs          Rob Whittle - Novell, Inc.
 Jasper Wong - Xionics               Don Wright - Lexmark
 Michael Wu - Heidelberg Digital     Rick Yardumian - Xerox
 Michael Yeung - Toshiba             Lloyd Young - Lexmark
 Atsushi Yuki - Kyocera              Peter Zehler - Xerox
 William Zhang- Canon Information    Frank Zhao - Panasonic
 Systems
 Steve Zilles - Adobe                Rob Zirnstein - Canon Information
                                     Systems

11. Formats for IPP Registration Proposals

 In order to propose an IPP extension for registration, the proposer
 must submit an application to IANA by email to "iana@iana.org" or by
 filling out the appropriate form on the IANA web pages
 (http://www.iana.org).  This section specifies the required
 information and the formats for proposing registrations of extensions
 to IPP as provided in Section 6 for:

Hastings, et al. Standards Track [Page 168] RFC 2911 IPP/1.1: Model and Semantics September 2000

    1. type2 'keyword' attribute values
    2. type3 'keyword' attribute values
    3. type2 'enum' attribute values
    4. type3 'enum' attribute values
    5. attributes
    6. attribute syntaxes
    7. operations
    8. status codes
    9. out-of-band attribute values

11.1 Type2 keyword attribute values registration,

 Type of registration:  type2 keyword attribute value
 Name of attribute to which this keyword specification is to be added:
 Proposed keyword name of this keyword value:
 Specification of this keyword value (follow the style of IPP Model
 Section 4.1.2.3):
 Name of proposer:
 Address of proposer:
 Email address of proposer:
 Note:  For type2 keywords, the Designated Expert will be the point of
 contact for the approved registration specification, if any
 maintenance of the registration specification is needed.

11.2 Type3 keyword attribute values registration

 Type of registration:  type3 keyword attribute value
 Name of attribute to which this keyword specification is to be added:
 Proposed keyword name of this keyword value:
 Specification of this keyword value (follow the style of IPP Model
 Section 4.1.2.3):
 Name of proposer:
 Address of proposer:
 Email address of proposer:
 Note:  For type3 keywords, the proposer will be the point of contact
 for the approved registration specification, if any maintenance of
 the registration specification is needed.

11.3 Type2 enum attribute values registration

 Type of registration:  type2 enum attribute value
 Name of attribute to which this enum specification is to be added:
 Keyword symbolic name of this enum value:
 Numeric value (to be assigned by the IPP Designated Expert in
 consultation with IANA):

Hastings, et al. Standards Track [Page 169] RFC 2911 IPP/1.1: Model and Semantics September 2000

 Specification of this enum value (follow the style of IPP Model
 Section 4.1.4):
 Name of proposer:
 Address of proposer:
 Email address of proposer:
 Note:  For type2 enums, the Designated Expert will be the point of
 contact for the approved registration specification, if any
 maintenance of the registration specification is needed.

11.4 Type3 enum attribute values registration

 Type of registration:  type3 enum attribute value
 Name of attribute to which this enum specification is to be added:
 Keyword symbolic name of this enum value:
 Numeric value (to be assigned by the IPP Designated Expert in
 consultation with IANA):
 Specification of this enum value (follow the style of IPP Model
 Section 4.1.4):
 Name of proposer:
 Address of proposer:
 Email address of proposer:
 Note:  For type3 enums, the proposer will be the point of contact for
 the approved registration specification, if any maintenance of the
 registration specification is needed.

11.5 Attribute registration

 Type of registration:  attribute
 Proposed keyword name of this attribute:
 Types of attribute (Operation, Job Template, Job Description, Printer
 Description):
 Operations to be used with if the attribute is an operation attribute:
 Object (Job, Printer, etc. if bound to an object):
 Attribute syntax(es) (include 1setOf and range as in Section 4.2):
 If attribute syntax is 'keyword' or 'enum', is it type2 or type3:
 If this is a Printer attribute, MAY the value returned depend on
 "document-format" (See Section 6.2):
 If this is a Job Template attribute, how does its specification depend
 on the value of the "multiple-document-handling" attribute:
 Specification of this attribute (follow the style of IPP Model Section
 4.2):
 Name of proposer:
 Address of proposer:
 Email address of proposer:

Hastings, et al. Standards Track [Page 170] RFC 2911 IPP/1.1: Model and Semantics September 2000

 Note:  For attributes, the IPP Designated Expert will be the point of
 contact for the approved registration specification, if any
 maintenance of the registration specification is needed.

11.6 Attribute Syntax registration

 Type of registration:  attribute syntax
 Proposed name of this attribute syntax:
 Type of attribute syntax (integer, octetString, character-string,  see
 [RFC2910]):
 Numeric tag according to [RFC2910] (to be assigned by the IPP
 Designated Expert in consultation with IANA):
 Specification of this attribute (follow the style of IPP Model Section
 4.1):
 Name of proposer:
 Address of proposer:
 Email address of proposer:
 Note:  For attribute syntaxes, the IPP Designated Expert will be the
 point of contact for the approved registration specification, if any
 maintenance of the registration specification is needed.

11.7 Operation registration

 Type of registration:  operation
 Proposed name of this operation:
 Numeric operation-id value according to section 4.4.15 (to be assigned
 by the IPP Designated Expert in consultation with IANA):
 Object Target (Job, Printer, etc. that operation is upon):
 Specification of this operation (follow the style of IPP Model Section
 3):
 Name of proposer:
 Address of proposer:
 Email address of proposer:
 Note:  For operations, the IPP Designated Expert will be the point of
 contact for the approved registration specification, if any
 maintenance of the registration specification is needed.

11.8 Attribute Group registration

 Type of registration:  attribute group
 Proposed name of this attribute group:
 Numeric tag according to [RFC2910] (to be assigned by the IPP
 Designated Expert in consultation with IANA):
 Operation requests and group number for each operation in which the
 attribute group occurs:

Hastings, et al. Standards Track [Page 171] RFC 2911 IPP/1.1: Model and Semantics September 2000

 Operation responses and group number for each operation in which the
 attribute group occurs:
 Specification of this attribute group (follow the style of IPP Model
 Section 3):
 Name of proposer:
 Address of proposer:
 Email address of proposer:
 Note:  For attribute groups, the IPP Designated Expert will be the
 point of contact for the approved registration specification, if any
 maintenance of the registration specification is needed.

11.9 Status code registration

 Type of registration:  status code
 Keyword symbolic name of this status code value:
 Numeric value (to be assigned by the IPP Designated Expert in
 consultation with IANA):
 Operations that this status code may be used with:
 Specification of this status code (follow the style of IPP Model
 Section 13 APPENDIX B:  Status Codes and Suggested Status Code
 Messages):
 Name of proposer:
 Address of proposer:
 Email address of proposer:
 Note:  For status codes, the Designated Expert will be the point of
 contact for the approved registration specification, if any
 maintenance of the registration specification is needed.

11.10 Out-of-band Attribute Value registration

 Type of registration:  out-of-band attribute value
 Proposed name of this out-of-band attribute value:
 Numeric tag according to [RFC2910] (to be assigned by the IPP Designated
 Expert in consultation with IANA):
 Operations that this out-of-band attribute value may be used with:
 Attributes that this out-of-band attribute value may be used with:
 Specification of this out-of-band attribute value (follow the style of
 the beginning of IPP Model Section 4.1):
 Name of proposer:
 Address of proposer:
 Email address of proposer:
 Note:  For out-of-band attribute values, the IPP Designated Expert
 will be the point of contact for the approved registration
 specification, if any maintenance of the registration specification
 is needed.

Hastings, et al. Standards Track [Page 172] RFC 2911 IPP/1.1: Model and Semantics September 2000

12. APPENDIX A: Terminology

 This specification document uses the terminology defined in this
 section.

12.1 Conformance Terminology

 The key words "MUST", "MUST NOT", "REQUIRED", "SHOULD", "SHOULD NOT",
 "RECOMMENDED", "MAY", and  "OPTIONAL" in this document are to be
 interpreted as described in RFC 2119 [RFC2119].

12.1.1 NEED NOT

 This term is not included in RFC 2119.  The verb "NEED NOT" indicates
 an action that the subject of the sentence does not have to implement
 in order to claim conformance to the standard.  The verb "NEED NOT"
 is used instead of "MAY NOT" since "MAY NOT" sounds like a
 prohibition.

12.2 Model Terminology

12.2.1 Keyword

 Keywords are used within this document as identifiers of semantic
 entities within the abstract model (see section 4.1.2.3).  Attribute
 names, some attribute values, attribute syntaxes, and attribute group
 names are represented as keywords.

12.2.2 Attributes

 An attribute is an item of information that is associated with an
 instance of an IPP object.  An attribute consists of an attribute
 name and one or more attribute values.  Each attribute has a specific
 attribute syntax.  All object attributes are defined in section 4 and
 all operation attributes are defined in section 3.
 Job Template Attributes are described in section 4.2. The client
 optionally supplies Job Template attributes in a create request
 (operation requests that create Job objects).  The Printer object has
 associated attributes which define supported and default values for
 the Printer.

12.2.2.1 Attribute Name

 Each attribute is uniquely identified in this document by its
 attribute name.  An attribute name is a keyword.  The keyword
 attribute name is given in the section header describing that

Hastings, et al. Standards Track [Page 173] RFC 2911 IPP/1.1: Model and Semantics September 2000

 attribute.  In running text in this document, attribute names are
 indicated inside double quotation marks (") where the quotation marks
 are not part of the keyword itself.

12.2.2.2 Attribute Group Name

 Related attributes are grouped into named groups.  The name of the
 group is a keyword.  The group name may be used in place of naming
 all the attributes in the group explicitly.  Attribute groups are
 defined in section 3.

12.2.2.3 Attribute Value

 Each attribute has one or more values.  Attribute values are
 represented in the syntax type specified for that attribute. In
 running text in this document, attribute values are indicated inside
 single quotation marks ('), whether their attribute syntax is
 keyword, integer, text, etc.  where the quotation marks are not part
 of the value itself.

12.2.2.4 Attribute Syntax

 Each attribute is defined using an explicit syntax type.  In this
 document, each syntax type is defined as a keyword with specific
 meaning.  The "Encoding and Transport" document [RFC2910] indicates
 the actual "on-the-wire" encoding rules for each syntax type.
 Attribute syntax types are defined in section 4.1.

12.2.3 Supports

 By definition, a Printer object supports an attribute only if that
 Printer object responds with the corresponding attribute populated
 with some value(s) in a response to a query for that attribute.  A
 Printer object supports an attribute value if the value is one of the
 Printer object's "supported values" attributes.  The device behind a
 Printer object may exhibit a behavior that corresponds to some IPP
 attribute, but if the Printer object, when queried for that
 attribute, doesn't respond with the attribute, then as far as IPP is
 concerned, that implementation does not support that feature. If the
 Printer object's "xxx-supported" attribute is not populated with a
 particular value (even if that value is a legal value for that
 attribute), then that Printer object does not support that particular
 value.

Hastings, et al. Standards Track [Page 174] RFC 2911 IPP/1.1: Model and Semantics September 2000

 A conforming implementation MUST support all REQUIRED attributes.
 However, even for REQUIRED attributes, conformance to IPP does not
 mandate that all implementations support all possible values
 representing all possible job processing behaviors and features.  For
 example, if a given instance of a Printer supports only certain
 document formats, then that Printer responds with the "document-
 format-supported" attribute populated with a set of values, possibly
 only one, taken from the entire set of possible values defined for
 that attribute. This limited set of values represents the Printer's
 set of supported document formats.  Supporting an attribute and some
 set of values for that attribute enables IPP end users to be aware of
 and make use of those features associated with that attribute and
 those values.  If an implementation chooses to not support an
 attribute or some specific value, then IPP end users would have no
 ability to make use of that feature within the context of IPP itself.
 However, due to existing practice and legacy systems which are not
 IPP aware, there might be some other mechanism outside the scope of
 IPP to control or request the "unsupported" feature (such as embedded
 instructions within the document data itself).
 For example, consider the "finishings-supported" attribute.
    1) If a Printer object is not physically capable of stapling, the
       "finishings-supported" attribute MUST NOT be populated with the
       value of 'staple'.
    2) A Printer object is physically capable of stapling, however an
       implementation chooses not to support stapling in the IPP
       "finishings" attribute.  In this case, 'staple' MUST NOT be a
       value in the "finishings-supported" Printer object attribute.
       Without support for the value 'staple', an IPP end user would
       have no means within the protocol itself to request that a Job
       be stapled.  However, an existing document data formatter might
       be able to request that the document be stapled directly with
       an embedded instruction within the document data.  In this
       case, the IPP implementation does not "support" stapling,
       however the end user is still able to have some control over
       the stapling of the completed job.
    3) A Printer object is physically capable of stapling, and an
       implementation chooses to support stapling in the IPP
       "finishings" attribute. In this case, 'staple' MUST be a value
       in the "finishings-supported" Printer object attribute. Doing
       so, would enable end users to be aware of and make use of the
       stapling feature using IPP attributes.

Hastings, et al. Standards Track [Page 175] RFC 2911 IPP/1.1: Model and Semantics September 2000

 Even though support for Job Template attributes by a Printer object
 is OPTIONAL, it is RECOMMENDED that if the device behind a Printer
 object is capable of realizing any feature or function that
 corresponds to an IPP attribute and some associated value, then that
 implementation SHOULD support that IPP attribute and value.
 The set of values in any of the supported value attributes is set
 (populated) by some administrative process or automatic sensing
 mechanism that is outside the scope of this IPP/1.1 document.  For
 administrative policy and control reasons, an administrator may
 choose to make only a subset of possible values visible to the end
 user.  In this case, the real output device behind the IPP Printer
 abstraction may be capable of a certain feature, however an
 administrator is specifying that access to that feature not be
 exposed to the end user through the IPP protocol.  Also, since a
 Printer object may represent a logical print device (not just a
 physical device) the actual process for supporting a value is
 undefined and left up to the implementation.  However, if a Printer
 object supports a value, some manual human action may be needed to
 realize the semantic action associated with the value, but no end
 user action is required.
 For example, if one of the values in the "finishings-supported"
 attribute is 'staple', the actual process might be an automatic
 staple action by a physical device controlled by some command sent to
 the device.  Or, the actual process of stapling might be a manual
 action by an operator at an operator attended Printer object.
 For another example of how supported attributes function, consider a
 system administrator who desires to control all print jobs so that no
 job sheets are printed in order to conserve paper.  To force no job
 sheets, the system administrator sets the only supported value for
 the "job-sheets-supported" attribute to 'none'.  In this case, if a
 client requests anything except 'none', the create request is
 rejected or the "job-sheets" value is ignored (depending on the value
 of "ipp-attribute-fidelity").  To force the use of job start/end
 sheets on all jobs, the administrator does not include the value
 'none' in the "job-sheets- supported" attribute.  In this case, if a
 client requests 'none', the create request is rejected or the "job-
 sheets" value is ignored (again depending on the value of "ipp-
 attribute-fidelity").

12.2.4 print-stream page

 A "print-stream page" is a page according to the definition of pages
 in the language used to express the document data.

Hastings, et al. Standards Track [Page 176] RFC 2911 IPP/1.1: Model and Semantics September 2000

12.2.5 impression

 An "impression" is the image (possibly many print-stream pages in
 different configurations) imposed onto a single media page.

13. APPENDIX B: Status Codes and Suggested Status Code Messages

 This section defines status code enum keywords and values that are
 used to provide semantic information on the results of an operation
 request.  Each operation response MUST include a status code.  The
 response MAY also contain a status message that provides a short
 textual description of the status.  The status code is intended for
 use by automata, and the status message is intended for the human end
 user.  Since the status message is an OPTIONAL component of the
 operation response, an IPP application (i.e., a browser, GUI, print
 driver or gateway) is NOT REQUIRED to examine or display the status
 message, since it MAY not be returned to the application.
 The prefix of the status keyword defines the class of response as
 follows:
    "informational" - Request received, continuing process
    "successful" - The action was successfully received, understood,
       and accepted
    "redirection" - Further action must be taken in order to complete
       the request
    "client-error" - The request contains bad syntax or cannot be
       fulfilled
    "server-error" - The IPP object  failed to fulfill an apparently
       valid request
 As with type2 enums, IPP status codes are extensible.  IPP clients
 are NOT REQUIRED to understand the meaning of all registered status
 codes, though such understanding is obviously desirable.  However,
 IPP clients MUST understand the class of any status code, as
 indicated by the prefix, and treat any unrecognized response as being
 equivalent to the first status code of that class, with the exception
 that an unrecognized response MUST NOT be cached.  For example, if an
 unrecognized status code of "client-error-xxx-yyy" is received by the
 client, it can safely assume that there was something wrong with its
 request and treat the response as if it had received a "client-
 error-bad-request" status code.  In such cases, IPP applications
 SHOULD present the OPTIONAL message (if present) to the end user
 since the message is likely to contain human readable information
 which will help to explain the unusual status.  The name of the enum
 is the suggested status message for US English.

Hastings, et al. Standards Track [Page 177] RFC 2911 IPP/1.1: Model and Semantics September 2000

 The status code values range from 0x0000 to 0x7FFF.  The value ranges
 for each status code class are as follows:
    "successful" - 0x0000 to 0x00FF
    "informational" - 0x0100 to 0x01FF
    "redirection" - 0x0200 to 0x02FF
    "client-error" - 0x0400 to 0x04FF
    "server-error" - 0x0500 to 0x05FF
 The top half (128 values) of each range (0x0n40 to 0x0nFF, for n = 0
 to 5) is reserved for vendor use within each status code class.
 Values 0x0600 to 0x7FFF are reserved for future assignment by IETF
 standards track documents and MUST NOT be used.

13.1 Status Codes

 Each status code is described below. Section 13.1.5.9 contains a
 table that indicates which status codes apply to which operations.
 The Implementer's Guide [IPP-IIG] describe the suggested steps for
 processing IPP attributes for all operations, including returning
 status codes.

13.1.1 Informational

 This class of status code indicates a provisional response and is to
 be used for informational purposes only.
 There are no status codes defined in IPP/1.1 for this class of status
 code.

13.1.2 Successful Status Codes

 This class of status code indicates that the client's request was
 successfully received, understood, and accepted.

13.1.2.1 successful-ok (0x0000)

 The request has succeeded and no request attributes were substituted
 or ignored.  In the case of a response to a create request, the
 'successful-ok' status code indicates that the request was
 successfully received and validated, and that the Job object has been
 created; it does not indicate that the job has been processed.  The
 transition of the Job object into the 'completed' state is the only
 indicator that the job has been printed.

Hastings, et al. Standards Track [Page 178] RFC 2911 IPP/1.1: Model and Semantics September 2000

13.1.2.2 successful-ok-ignored-or-substituted-attributes (0x0001)

 The request has succeeded, but some supplied (1) attributes were
 ignored or (2) unsupported values were substituted with supported
 values or were ignored in order to perform the operation without
 rejecting it.  Unsupported attributes, attribute syntaxes, or values
 MUST be returned in the Unsupported Attributes group of the response
 for all operations.  There is an exception to this rule for the query
 operations:  Get-Printer-Attributes, Get-Jobs, and Get-Job-Attributes
 for the "requested-attributes" operation attribute only.  When the
 supplied values of the "requested-attributes" operation attribute are
 requesting attributes that are not supported, the IPP object MAY, but
 is NOT REQUIRED to, return the "requested-attributes" attribute in
 the Unsupported Attribute response group (with the unsupported values
 only).  See sections 3.1.7 and 3.2.1.2.

13.1.2.3 successful-ok-conflicting-attributes (0x0002)

 The request has succeeded, but some supplied attribute values
 conflicted with the values of other supplied attributes.  These
 conflicting values were either (1) substituted with (supported)
 values or (2) the attributes were removed in order to process the job
 without rejecting it.  Attributes or values which conflict with other
 attributes and have been substituted or ignored MUST be returned in
 the Unsupported Attributes group of the response for all operations
 as supplied by the client.  See sections 3.1.7 and 3.2.1.2.

13.1.3 Redirection Status Codes

 This class of status code indicates that further action needs to be
 taken to fulfill the request.
 There are no status codes defined in IPP/1.1 for this class of status
 code.

13.1.4 Client Error Status Codes

 This class of status code is intended for cases in which the client
 seems to have erred.  The IPP object SHOULD return a message
 containing an explanation of the error situation and whether it is a
 temporary or permanent condition.

Hastings, et al. Standards Track [Page 179] RFC 2911 IPP/1.1: Model and Semantics September 2000

13.1.4.1 client-error-bad-request (0x0400)

 The request could not be understood by the IPP object due to
 malformed syntax (such as the value of a fixed length attribute whose
 length does not match the prescribed length for that attribute - see
 the Implementer's Guide [IPP-IIG] ).  The IPP application SHOULD NOT
 repeat the request without modifications.

13.1.4.2 client-error-forbidden (0x0401)

 The IPP object understood the request, but is refusing to fulfill it.
 Additional authentication information or authorization credentials
 will not help and the request SHOULD NOT be repeated.  This status
 code is commonly used when the IPP object does not wish to reveal
 exactly why the request has been refused or when no other response is
 applicable.

13.1.4.3 client-error-not-authenticated (0x0402)

 The request requires user authentication.  The IPP client may repeat
 the request with suitable authentication information. If the request
 already included authentication information, then this status code
 indicates that authorization has been refused for those credentials.
 If this response contains the same challenge as the prior response,
 and the user agent has already attempted authentication at least
 once, then the response message may contain relevant diagnostic
 information.  This status codes reveals more information than
 "client-error-forbidden".

13.1.4.4 client-error-not-authorized (0x0403)

 The requester is not authorized to perform the request.  Additional
 authentication information or authorization credentials will not help
 and the request SHOULD NOT be repeated.  This status code is used
 when the IPP object wishes to reveal that the authentication
 information is understandable, however, the requester is explicitly
 not authorized to perform the request.  This status codes reveals
 more information than "client-error-forbidden" and "client-error-
 not-authenticated".

13.1.4.5 client-error-not-possible (0x0404)

 This status code is used when the request is for something that can
 not happen.  For example, there might be a request to cancel a job
 that has already been canceled or aborted by the system.  The IPP
 client SHOULD NOT repeat the request.

Hastings, et al. Standards Track [Page 180] RFC 2911 IPP/1.1: Model and Semantics September 2000

13.1.4.6 client-error-timeout (0x0405)

 The client did not produce a request within the time that the IPP
 object was prepared to wait.  For example, a client issued a Create-
 Job operation and then, after a long period of time, issued a Send-
 Document operation and this error status code was returned in
 response to the Send-Document request  (see section 3.3.1).  The IPP
 object might have been forced to clean up resources that had been
 held for the waiting additional Documents.  The IPP object was forced
 to close the Job since the client took too long.  The client SHOULD
 NOT repeat the request without modifications.

13.1.4.7 client-error-not-found (0x0406)

 The IPP object has not found anything matching the request URI.  No
 indication is given of whether the condition is temporary or
 permanent.  For example, a client with an old reference to a Job (a
 URI) tries to cancel the Job, however in the mean time the Job might
 have been completed and all record of it at the Printer has been
 deleted.  This status code, 'client-error-not-found' is returned
 indicating that the referenced Job can not be found.  This error
 status code is also used when a client supplies a URI as a reference
 to the document data in either a Print-URI or Send-URI operation, but
 the document can not be found.
 In practice, an IPP application should avoid a not found situation by
 first querying and presenting a list of valid Printer URIs and Job
 URIs to the end-user.

13.1.4.8 client-error-gone (0x0407)

 The requested object is no longer available and no forwarding address
 is known.  This condition should be considered permanent.  Clients
 with link editing capabilities should delete references to the
 request URI after user approval.  If the IPP object does not know or
 has no facility to determine, whether or not the condition is
 permanent, the status code "client-error-not-found" should be used
 instead.
 This response is primarily intended to assist the task of maintenance
 by notifying the recipient that the resource is intentionally
 unavailable and that the IPP object administrator desires that remote
 links to that resource be removed. It is not necessary to mark all
 permanently unavailable resources as "gone" or to keep the mark for
 any length of time -- that is left to the discretion of the IPP
 object administrator and/or Printer implementation.

Hastings, et al. Standards Track [Page 181] RFC 2911 IPP/1.1: Model and Semantics September 2000

13.1.4.9 client-error-request-entity-too-large (0x0408)

 The IPP object is refusing to process a request because the request
 entity is larger than the IPP object is willing or able to process.
 An IPP Printer returns this status code when it limits the size of
 print jobs and it receives a print job that exceeds that limit or
 when the attributes are so many that their encoding causes the
 request entity to exceed IPP object capacity.

13.1.4.10 client-error-request-value-too-long (0x0409)

 The IPP object is refusing to service the request because one or more
 of the client-supplied attributes has a variable length value that is
 longer than the maximum length specified for that attribute.  The IPP
 object might not have sufficient resources (memory, buffers, etc.) to
 process (even temporarily), interpret, and/or ignore a value larger
 than the maximum length.  Another use of this error code is when the
 IPP object supports the processing of a large value that is less than
 the maximum length, but during the processing of the request as a
 whole, the object may pass the value onto some other system component
 which is not able to accept the large value.  For more details, see
 the Implementer's Guide [IPP-IIG] .
 Note:  For attribute values that are URIs, this rare condition is
 only likely to occur when a client has improperly submitted a request
 with long query information (e.g. an IPP application allows an end-
 user to enter an invalid URI), when the client has descended into a
 URI "black hole" of redirection (e.g., a redirected URI prefix that
 points to a suffix of itself), or when the IPP object is under attack
 by a client attempting to exploit security holes present in some IPP
 objects using fixed-length buffers for reading or manipulating the
 Request-URI.

13.1.4.11 client-error-document-format-not-supported (0x040A)

 The IPP object is refusing to service the request because the
 document data is in a format, as specified in the "document-format"
 operation attribute, that is not supported by the Printer object.
 This error is returned independent of the client-supplied "ipp-
 attribute-fidelity".  The Printer object MUST return this status
 code, even if there are other Job Template attributes that are not
 supported as well, since this error is a bigger problem than with Job
 Template attributes.  See sections 3.1.6.1, 3.1.7, and 3.2.1.1.

Hastings, et al. Standards Track [Page 182] RFC 2911 IPP/1.1: Model and Semantics September 2000

13.1.4.12 client-error-attributes-or-values-not-supported (0x040B)

 In a create request, if the Printer object does not support one or
 more attributes, attribute syntaxes, or attribute values supplied in
 the request and the client supplied the "ipp-attribute-fidelity"
 operation attribute with the 'true' value, the Printer object MUST
 return this status code.  The Printer object MUST also return in the
 Unsupported Attributes Group all the attributes and/or values
 supplied by the client that are not supported.  See section 3.1.7.
 For example, if the request indicates 'iso-a4' media, but that media
 type is not supported by the Printer object.  Or, if the client
 supplies a Job Template attribute and the attribute itself is not
 even supported by the Printer.  If the "ipp-attribute-fidelity"
 attribute is 'false', the Printer MUST ignore or substitute values
 for unsupported Job Template attributes and values rather than reject
 the request and return this status code.
 For any operation where a client requests attributes (such as a Get-
 Jobs, Get-Printer-Attributes, or Get-Job-Attributes operation), if
 the IPP object does not support one or more of the requested
 attributes, the IPP object simply ignores the unsupported requested
 attributes and processes the request as if they had not been
 supplied, rather than returning this status code.  In this case, the
 IPP object MUST return the 'successful-ok-ignored-or-substituted-
 attributes' status code and MAY return the unsupported attributes as
 values of the "requested-attributes" in the Unsupported Attributes
 Group (see section 13.1.2.2).

13.1.4.13 client-error-uri-scheme-not-supported (0x040C)

 The scheme of the client-supplied URI in a Print-URI or a Send-URI
 operation is not supported.  See sections 3.1.6.1 and 3.1.7.

13.1.4.14 client-error-charset-not-supported (0x040D)

 For any operation, if the IPP Printer does not support the charset
 supplied by the client in the "attributes-charset" operation
 attribute, the Printer MUST reject the operation and return this
 status and any 'text' or 'name' attributes using the 'utf-8' charset
 (see Section 3.1.4.1).  See sections 3.1.6.1 and  3.1.7.

13.1.4.15 client-error-conflicting-attributes (0x040E)

 The request is rejected because some attribute values conflicted with
 the values of other attributes which this document does not permit to
 be substituted or ignored.  The Printer object MUST also return in
 the Unsupported Attributes Group the conflicting attributes supplied
 by the client.  See sections 3.1.7 and 3.2.1.2.

Hastings, et al. Standards Track [Page 183] RFC 2911 IPP/1.1: Model and Semantics September 2000

13.1.4.16 client-error-compression-not-supported (0x040F)

 The IPP object is refusing to service the request because the
 document data, as specified in the "compression" operation attribute,
 is compressed in a way that is not supported by the Printer object.
 This error is returned independent of the client-supplied "ipp-
 attribute-fidelity".  The Printer object MUST return this status
 code, even if there are other Job Template attributes that are not
 supported as well, since this error is a bigger problem than with Job
 Template attributes.  See sections 3.1.6.1, 3.1.7, and 3.2.1.1.

13.1.4.17 client-error-compression-error (0x0410)

 The IPP object is refusing to service the request because the
 document data cannot be decompressed when using the algorithm
 specified by the "compression" operation attribute.  This error is
 returned independent of the client-supplied "ipp-attribute-fidelity".
 The Printer object MUST return this status code, even if there are
 Job Template attributes that are not supported as well, since this
 error is a bigger problem than with Job Template attributes.  See
 sections 3.1.7 and 3.2.1.1.

13.1.4.18 client-error-document-format-error (0x0411)

 The IPP object is refusing to service the request because Printer
 encountered an error in the document data while interpreting it.
 This error is returned independent of the client-supplied "ipp-
 attribute-fidelity".  The Printer object MUST return this status
 code, even if there are Job Template attributes that are not
 supported as well, since this error is a bigger problem than with Job
 Template attributes.  See sections 3.1.7 and 3.2.1.1.

13.1.4.19 client-error-document-access-error (0x0412)

 The IPP object is refusing to service the Print-URI or Send-URI
 request because Printer encountered an access error while attempting
 to validate the accessibility or access the document data specified
 in the "document-uri" operation attribute.  The Printer MAY also
 return a specific document access error code using the "document-
 access-error" operation attribute (see section 3.1.6.4).  This error
 is returned independent of the client-supplied "ipp-attribute-
 fidelity".  The Printer object MUST return this status code, even if
 there are Job Template attributes that are not supported as well,
 since this error is a bigger problem than with Job Template
 attributes.  See sections 3.1.6.1 and 3.1.7.

Hastings, et al. Standards Track [Page 184] RFC 2911 IPP/1.1: Model and Semantics September 2000

13.1.5 Server Error Status Codes

 This class of status codes indicates cases in which the IPP object is
 aware that it has erred or is incapable of performing the request.
 The IPP object SHOULD include a message containing an explanation of
 the error situation, and whether it is a temporary or permanent
 condition.

13.1.5.1 server-error-internal-error (0x0500)

 The IPP object encountered an unexpected condition that prevented it
 from fulfilling the request.  This error status code differs from
 "server-error-temporary-error" in that it implies a more permanent
 type of internal error.  It also differs from "server-error-device-
 error" in that it implies an unexpected condition (unlike a paper-jam
 or out-of-toner problem which is undesirable but expected).  This
 error status code indicates that probably some knowledgeable human
 intervention is required.

13.1.5.2 server-error-operation-not-supported (0x0501)

 The IPP object does not support the functionality required to fulfill
 the request. This is the appropriate response when the IPP object
 does not recognize an operation or is not capable of supporting it.
 See sections 3.1.6.1 and 3.1.7.

13.1.5.3 server-error-service-unavailable (0x0502)

 The IPP object is currently unable to handle the request due to a
 temporary overloading or maintenance of the IPP object.  The
 implication is that this is a temporary condition which will be
 alleviated after some delay. If known, the length of the delay may be
 indicated in the message.  If no delay is given, the IPP application
 should handle the response as it would for a "server-error-
 temporary-error" response.  If the condition is more permanent, the
 error status codes "client-error-gone" or "client-error-not-found"
 could be used.

13.1.5.4 server-error-version-not-supported (0x0503)

 The IPP object does not support, or refuses to support, the IPP
 protocol version that was supplied as the value of the "version-
 number" operation parameter in the request.  The IPP object is
 indicating that it is unable or unwilling to complete the request
 using the same major and minor version number as supplied in the
 request other than with this error message. The error response SHOULD
 contain a "status-message" attribute (see section 3.1.6.2) describing

Hastings, et al. Standards Track [Page 185] RFC 2911 IPP/1.1: Model and Semantics September 2000

 why that version is not supported and what other versions are
 supported by that IPP object.  See sections 3.1.6.1, 3.1.7, and
 3.1.8.
 The error response MUST identify in the "version-number" operation
 parameter the closest version number that the IPP object does
 support.  For example, if a client supplies version '1.0' and an
 IPP/1.1 object supports version '1.0', then it responds with version
 '1.0' in all responses to such a request.  If the IPP/1.1 object does
 not support version '1.0', then it should accept the request and
 respond with version '1.1' or may reject the request and respond with
 this error code and version
 '1.1'.  If a client supplies a version '1.2', the IPP/1.1 object
 should accept the request and return version '1.1' or may reject the
 request and respond with this error code and version '1.1'.  See
 sections 3.1.8 and 4.4.14.

13.1.5.5 server-error-device-error (0x0504)

 A printer error, such as a paper jam, occurs while the IPP object
 processes a Print or Send operation.  The response contains the true
 Job Status (the values of the "job-state" and "job-state-reasons"
 attributes).  Additional information can be returned in the OPTIONAL
 "job-state-message" attribute value or in the OPTIONAL status message
 that describes the error in more detail.  This error status code is
 only returned in situations where the Printer is unable to accept the
 create request because of such a device error.  For example, if the
 Printer is unable to spool, and can only accept one job at a time,
 the reason it might reject a create request is that the printer
 currently has a paper jam.  In many cases however, where the Printer
 object can accept the request even though the Printer has some error
 condition, the 'successful-ok' status code will be returned.  In such
 a case, the client would look at the returned Job Object Attributes
 or later query the Printer to determine its state and state reasons.

13.1.5.6 server-error-temporary-error (0x0505)

 A temporary error such as a buffer full write error, a memory
 overflow (i.e. the document data exceeds the memory of the Printer),
 or a disk full condition, occurs while the IPP Printer processes an
 operation.  The client MAY try the unmodified request again at some
 later point in time with an expectation that the temporary internal
 error condition may have been cleared.  Alternatively, as an
 implementation option, a Printer object MAY delay the response until
 the temporary condition is cleared so that no error is returned.

Hastings, et al. Standards Track [Page 186] RFC 2911 IPP/1.1: Model and Semantics September 2000

13.1.5.7 server-error-not-accepting-jobs (0x0506)

 A temporary error indicating that the Printer is not currently
 accepting jobs, because the administrator has set the value of the
 Printer's "printer-is-accepting-jobs" attribute to 'false' (by means
 outside the scope of this IPP/1.1 document).

13.1.5.8 server-error-busy (0x0507)

 A temporary error indicating that the Printer is too busy processing
 jobs and/or other requests. The client SHOULD try the unmodified
 request again at some later point in time with an expectation that
 the temporary busy condition will have been cleared.

13.1.5.9 server-error-job-canceled (0x0508)

 An error indicating that the job has been canceled by an operator or
 the system while the client was transmitting the data to the IPP
 Printer.  If a job-id and job-uri had been created, then they are
 returned in the Print-Job, Send-Document, or Send-URI response as
 usual; otherwise, no job-id and job-uri are returned in the response.

13.1.5.10 server-error-multiple-document-jobs-not-supported (0x0509)

 The IPP object does not support multiple documents per job and a
 client attempted to supply document data with a second Send-Document
 or Send-URI operation.

13.2 Status Codes for IPP Operations

 PJ = Print-Job, PU = Print-URI, CJ = Create-Job, SD = Send-Document
 SU = Send-URI, V = Validate-Job, GA = Get-Job-Attributes and
 Get-Printer-Attributes, GJ = Get-Jobs, C = Cancel-Job

Hastings, et al. Standards Track [Page 187] RFC 2911 IPP/1.1: Model and Semantics September 2000

                                                IPP Operations
 IPP Status Keyword                       PJ PU CJ SD SU V GA GJ C
 ------------------                       -- -- -- -- -- - -- -- -
 successful-ok                            x  x  x  x  x  x x  x  x
 successful-ok-ignored-or-substituted-    x  x  x  x  x  x x  x  x
      attributes
 successful-ok-conflicting-attributes     x  x  x  x  x  x x  x  x
 client-error-bad-request                 x  x  x  x  x  x x  x  x
 client-error-forbidden                   x  x  x  x  x  x x  x  x
 client-error-not-authenticated           x  x  x  x  x  x x  x  x
 client-error-not-authorized              x  x  x  x  x  x x  x  x
 client-error-not-possible                x  x  x  x  x  x x  x  x
 client-error-timeout                              x  x
 client-error-not-found                   x  x  x  x  x  x x  x  x
 client-error-gone                        x  x  x  x  x  x x  x  x
 client-error-request-entity-too-large    x  x  x  x  x  x x  x  x
 client-error-request-value-too-long      x  x  x  x  x  x x  x  x
 client-error-document-format-not-        x  x     x  x  x x
      supported
 client-error-attributes-or-values-not-   x  x  x  x  x  x x  x  x
      supported
 client-error-uri-scheme-not-supported       x        x
 client-error-charset-not-supported       x  x  x  x  x  x x  x  x
 client-error-conflicting-attributes      x  x  x  x  x  x x  x  x
 client-error-compression-not-supported   x  x     x  x  x
 client-error-compression-error           x  x     x  x
 client-error-document-format-error       x  x     x  x
 client-error-document-access-error          x        x
 server-error-internal-error              x  x  x  x  x  x x  x  x
 server-error-operation-not-supported        x  x  x  x
 server-error-service-unavailable         x  x  x  x  x  x x  x  x
 server-error-version-not-supported       x  x  x  x  x  x x  x  x
 server-error-device-error                x  x  x  x  x
 server-error-temporary-error             x  x  x  x  x
 server-error-not-accepting-jobs          x  x  x        x
 server-error-busy                        x  x  x  x  x  x x  x  x
 server-error-job-canceled                x        x  x
 server-error-multiple-document-jobs-              x  x
        not-supported
 HJ = Hold-Job, RJ = Release-Job, RS = Restart-Job
 PP = Pause-Printer, RP = Resume-Printer, PJ = Purge-Jobs

Hastings, et al. Standards Track [Page 188] RFC 2911 IPP/1.1: Model and Semantics September 2000

                                          IPP Operations (cont.)
 IPP Status Keyword                       HJ RJ RS PP RP PJ
 ------------------                       -- -- -- -- -- --
 successful-ok                            x  x  x  x  x  x
 successful-ok-ignored-or-substituted-    x  x  x  x  x  x
      attributes
 successful-ok-conflicting-attributes     x  x  x  x  x  x
 client-error-bad-request                 x  x  x  x  x  x
 client-error-forbidden                   x  x  x  x  x  x
 client-error-not-authenticated           x  x  x  x  x  x
 client-error-not-authorized              x  x  x  x  x  x
 client-error-not-possible                x  x  x  x  x  x
 client-error-timeout
 client-error-not-found                   x  x  x  x  x  x
 client-error-gone                        x  x  x  x  x  x
 client-error-request-entity-too-large    x  x  x  x  x  x
 client-error-request-value-too-long      x  x  x  x  x  x
 client-error-document-format-not-
      supported
 client-error-attributes-or-values-not-   x  x  x  x  x  x
      supported
 client-error-uri-scheme-not-supported
 client-error-charset-not-supported       x  x  x  x  x  x
 client-error-conflicting-attributes      x  x  x  x  x  x
 client-error-compression-not-supported
 client-error-compression-error
 client-error-document-format-error
 client-error-document-access-error
 server-error-internal-error              x  x  x  x  x  x
 server-error-operation-not-supported     x  x  x  x  x  x
 server-error-service-unavailable         x  x  x  x  x  x
 server-error-version-not-supported       x  x  x  x  x  x
 server-error-device-error
 server-error-temporary-error             x  x  x  x  x  x
 server-error-not-accepting-jobs
 server-error-busy                        x  x  x  x  x  x
 server-error-job-canceled
 server-error-multiple-document-jobs-
        not-supported

Hastings, et al. Standards Track [Page 189] RFC 2911 IPP/1.1: Model and Semantics September 2000

14. APPENDIX C: "media" keyword values

 Standard keyword values are taken from several sources.
 Standard values are defined (taken from DPA[ISO10175] and the Printer
 MIB[RFC1759]):
  'default': The default medium for the output device
  'iso-a4-white': Specifies the ISO A4 white medium: 210 mm x 297 mm
  'iso-a4-colored': Specifies the ISO A4 colored medium: 210 mm x 297
     mm
  'iso-a4-transparent' Specifies the ISO A4 transparent medium: 210 mm
     x 297 mm
  'iso-a3-white': Specifies the ISO A3 white medium: 297 mm x 420 mm
  'iso-a3-colored': Specifies the ISO A3 colored medium: 297 mm x 420
     mm
  'iso-a5-white': Specifies the ISO A5 white medium: 148 mm x 210 mm
  'iso-a5-colored': Specifies the ISO A5 colored medium: 148 mm x 210
     mm
  'iso-b4-white': Specifies the ISO B4 white medium: 250 mm x 353 mm
  'iso-b4-colored': Specifies the ISO B4 colored medium: 250 mm x 353
     mm
  'iso-b5-white': Specifies the ISO B5 white medium: 176 mm x 250 mm
  'iso-b5-colored': Specifies the ISO B5 colored medium: 176 mm x 250
     mm
  'jis-b4-white': Specifies the JIS B4 white medium: 257 mm x 364 mm
  'jis-b4-colored': Specifies the JIS B4 colored medium: 257 mm x 364
     mm
  'jis-b5-white': Specifies the JIS B5 white medium: 182 mm x 257 mm
  'jis-b5-colored': Specifies the JIS B5 colored medium: 182 mm x 257
     mm
 The following standard values are defined for North American media:
  'na-letter-white': Specifies the North American letter white medium
  'na-letter-colored': Specifies the North American letter colored
     medium
  'na-letter-transparent': Specifies the North American letter
     transparent medium
  'na-legal-white': Specifies the North American legal white medium
  'na-legal-colored': Specifies the North American legal colored
     medium

Hastings, et al. Standards Track [Page 190] RFC 2911 IPP/1.1: Model and Semantics September 2000

 The following standard values are defined for envelopes:
  'iso-b4-envelope': Specifies the ISO B4 envelope medium
  'iso-b5-envelope': Specifies the ISO B5 envelope medium
  'iso-c3-envelope': Specifies the ISO C3 envelope medium
  'iso-c4-envelope': Specifies the ISO C4 envelope medium
  'iso-c5-envelope': Specifies the ISO C5 envelope medium
  'iso-c6-envelope': Specifies the ISO C6 envelope medium
  'iso-designated-long-envelope': Specifies the ISO Designated Long
     envelope medium
  'na-10x13-envelope': Specifies the North American 10x13 envelope
     medium
  'na-9x12-envelope': Specifies the North American 9x12 envelope
     medium
  'monarch-envelope': Specifies the Monarch envelope
  'na-number-10-envelope': Specifies the North American number 10
     business envelope medium
  'na-7x9-envelope': Specifies the North American 7x9 inch envelope
  'na-9x11-envelope': Specifies the North American 9x11 inch
     envelope
  'na-10x14-envelope': Specifies the North American 10x14 inch
     envelope
  'na-number-9-envelope': Specifies the North American number 9
     business envelope
  'na-6x9-envelope': Specifies the North American 6x9 inch envelope
  'na-10x15-envelope': Specifies the North American 10x15 inch
     envelope
 The following standard values are defined for the less commonly used
 media:

'executive-white': Specifies the white executive medium 'folio-white': Specifies the folio white medium 'invoice-white': Specifies the white invoice medium 'ledger-white': Specifies the white ledger medium 'quarto-white': Specified the white quarto medium 'iso-a0-white': Specifies the ISO A0 white medium: 841 mm x 1189 mm 'iso-a0-transparent': Specifies the ISO A0 transparent medium: 841 mm

  x 1189 mm

'iso-a0-translucent': Specifies the ISO A0 translucent medium: 841 mm

  x 1189 mm

'iso-a1-white': Specifies the ISO A1 white medium: 594 mm x 841 mm 'iso-a1-transparent': Specifies the ISO A1 transparent medium: 594 mm

  x 841 mm

'iso-a1-translucent': Specifies the ISO A1 translucent medium: 594 mm

  x 841 mm

'iso-a2-white': Specifies the ISO A2 white medium: 420 mm x 594 mm

Hastings, et al. Standards Track [Page 191] RFC 2911 IPP/1.1: Model and Semantics September 2000

'iso-a2-transparent': Specifies the ISO A2 transparent medium: 420 mm

  x 594 mm

'iso-a2-translucent': Specifies the ISO A2 translucent medium: 420 mm

  x 594 mm

'iso-a3-transparent': Specifies the ISO A3 transparent medium: 297 mm

  x 420 mm

'iso-a3-translucent': Specifies the ISO A3 translucent medium: 297 mm

  x 420 mm

'iso-a4-translucent': Specifies the ISO A4 translucent medium: 210 mm

  x 297 mm

'iso-a5-transparent': Specifies the ISO A5 transparent medium: 148 mm

  x 210 mm

'iso-a5-translucent': Specifies the ISO A5 translucent medium: 148 mm

  x 210 mm

'iso-a6-white': Specifies the ISO A6 white medium: 105 mm x 148 mm 'iso-a7-white': Specifies the ISO A7 white medium: 74 mm x 105 mm 'iso-a8-white': Specifies the ISO A8 white medium: 52 mm x 74 mm 'iso-a9-white': Specifies the ISO A9 white medium: 37 mm x 52 mm 'iso-a10-white': Specifies the ISO A10 white medium: 26 mm x 37 mm 'iso-b0-white': Specifies the ISO B0 white medium: 1000 mm x 1414 mm 'iso-b1-white': Specifies the ISO B1 white medium: 707 mm x 1000 mm 'iso-b2-white': Specifies the ISO B2 white medium: 500 mm x 707 mm 'iso-b3-white': Specifies the ISO B3 white medium: 353 mm x 500 mm 'iso-b6-white': Specifies the ISO B6 white medium: 125 mm x 176 mm 'iso-b7-white': Specifies the ISO B7 white medium: 88 mm x 125 mm 'iso-b8-white': Specifies the ISO B8 white medium: 62 mm x 88 mm 'iso-b9-white': Specifies the ISO B9 white medium: 44 mm x 62 mm 'iso-b10-white': Specifies the ISO B10 white medium: 31 mm x 44 mm 'jis-b0-white': Specifies the JIS B0 white medium: 1030 mm x 1456 mm 'jis-b0-transparent': Specifies the JIS B0 transparent medium: 1030

  mm x 1456 mm

'jis-b0-translucent': Specifies the JIS B0 translucent medium: 1030

  mm x 1456 mm

'jis-b1-white': Specifies the JIS B1 white medium: 728 mm x 1030 mm 'jis-b1-transparent': Specifies the JIS B1 transparent medium: 728 mm

  x 1030 mm

'jis-b1-translucent': Specifies the JIS B1 translucent medium: 728 mm

  x 1030 mm

'jis-b2-white': Specifies the JIS B2 white medium: 515 mm x 728 mm 'jis-b2-transparent': Specifies the JIS B2 transparent medium: 515 mm

  x 728 mm

'jis-b2-translucent': Specifies the JIS B2 translucent medium: 515 mm

  x 728 mm

'jis-b3-white': Specifies the JIS B3 white medium: 364 mm x 515 mm 'jis-b3-transparent': Specifies the JIS B3 transparent medium: 364 mm

  x 515 mm

'jis-b3-translucent': Specifies the JIS B3 translucent medium: 364 mm

  x 515 mm

Hastings, et al. Standards Track [Page 192] RFC 2911 IPP/1.1: Model and Semantics September 2000

'jis-b4-transparent': Specifies the JIS B4 transparent medium: 257 mm

  x 364 mm

'jis-b4-translucent': Specifies the JIS B4 translucent medium: 257 mm

  x 364 mm

'jis-b5-transparent': Specifies the JIS B5 transparent medium: 182 mm

  x 257 mm

'jis-b5-translucent': Specifies the JIS B5 translucent medium: 182 mm

  x 257 mm

'jis-b6-white': Specifies the JIS B6 white medium: 128 mm x 182 mm 'jis-b7-white': Specifies the JIS B7 white medium: 91 mm x 128 mm 'jis-b8-white': Specifies the JIS B8 white medium: 64 mm x 91 mm 'jis-b9-white': Specifies the JIS B9 white medium: 45 mm x 64 mm 'jis-b10-white': Specifies the JIS B10 white medium: 32 mm x 45 mm

 The following standard values are defined for American Standard (i.e.
 ANSI) engineering media:
  'a-white': Specifies the engineering ANSI A size white medium: 8.5
     inches x 11 inches
  'a-transparent': Specifies the engineering ANSI A size transparent
     medium: 8.5 inches x 11 inches
  'a-translucent': Specifies the engineering ANSI A size translucent
     medium: 8.5 inches x 11 inches
  'b-white': Specifies the engineering ANSI B size white medium: 11
     inches x 17 inches
  'b-transparent': Specifies the engineering ANSI B size transparent
     medium: 11 inches x 17 inches)
  'b-translucent': Specifies the engineering ANSI B size translucent
     medium: 11 inches x 17 inches
  'c-white': Specifies the engineering ANSI C size white medium: 17
     inches x 22 inches
  'c-transparent': Specifies the engineering ANSI C size transparent
     medium: 17 inches x 22 inches
  'c-translucent': Specifies the engineering ANSI C size translucent
     medium: 17 inches x 22 inches
  'd-white': Specifies the engineering ANSI D size white medium: 22
     inches x 34 inches
  'd-transparent': Specifies the engineering ANSI D size transparent
     medium: 22 inches x 34 inches
  'd-translucent': Specifies the engineering ANSI D size translucent
     medium: 22 inches x 34 inches
  'e-white': Specifies the engineering ANSI E size white medium: 34
     inches x 44 inches
  'e-transparent': Specifies the engineering ANSI E size transparent
     medium: 34 inches x 44 inches
  'e-translucent': Specifies the engineering ANSI E size translucent
     medium: 34 inches x 44 inches

Hastings, et al. Standards Track [Page 193] RFC 2911 IPP/1.1: Model and Semantics September 2000

 The following standard values are defined for American Standard (i.e.
 ANSI) engineering media for devices that provide the "synchro-cut"
 feature (see section 14.1):

'axsynchro-white': Specifies the roll paper having the width of the

  longer edge (11 inches) of the engineering ANSI A size white medium
  and cuts synchronizing with data.

'axsynchro-transparent': Specifies the roll paper having the width of

  the longer edge (11 inches) of the engineering ANSI A size
  transparent medium and cuts synchronizing with data.

'axsynchro-translucent': Specifies the roll paper having the width of

  the longer edge (11 inches) of the engineering ANSI A size
  translucent medium and cuts synchronizing with data.

'bxsynchro-white': Specifies the roll paper having the width of the

  longer edge (17 inches) of the engineering ANSI B size white medium
  and cuts synchronizing with data.

'bxsynchro-transparent': Specifies the roll paper having the width of

  the longer edge (17 inches) of the engineering ANSI B size
  transparent medium and cuts synchronizing with data.

'bxsynchro-translucent': Specifies the roll paper having the width of

  the longer edge (17 inches) of the engineering ANSI B size
  translucent medium and cuts synchronizing with data.

'cxsynchro-white': Specifies the roll paper having the width of the

  longer edge (22 inches) of the engineering ANSI C size white medium
  and cuts synchronizing with data.

'cxsynchro-transparent': Specifies the roll paper having the width of

  the longer edge (22 inches) of the engineering ANSI C size
  transparent medium and cuts synchronizing with data.

'cxsynchro-translucent': Specifies the roll paper having the width of

  the longer edge (22 inches) of the engineering ANSI C size
  translucent medium and cuts synchronizing with data.

'dxsynchro-white': Specifies the roll paper having the width of the

  longer edge (34 inches) of the engineering ANSI D size white medium
  and cuts synchronizing with data.

'dxsynchro-transparent': Specifies the roll paper having the width of

  the longer edge (34 inches) of the engineering ANSI D size
  transparent medium and cuts synchronizing with data.

'dxsynchro-translucent': Specifies the roll paper having the width of

  the longer edge (34 inches) of the engineering ANSI D size
  translucent medium and cuts synchronizing with data.

'exsynchro-white': Specifies the roll paper having the width of the

  longer edge (44 inches) of the engineering ANSI E size white medium
  and cuts synchronizing with data.

'exsynchro-transparent': Specifies the roll paper having the width of

  the longer edge (44 inches) of the engineering ANSI E size
  transparent medium and cuts synchronizing with data.

Hastings, et al. Standards Track [Page 194] RFC 2911 IPP/1.1: Model and Semantics September 2000

'exsynchro-translucent': Specifies the roll paper having the width of

  the longer edge (44 inches) of the engineering ANSI E size
  translucent medium and cuts synchronizing with data.
 The following standard values are defined for American Architectural
 engineering media:

'arch-a-white': Specifies the Architectural A size white medium: 9

  inches x 12 inches

'arch-a-transparent': Specifies the Architectural A size transparent

  medium: 9 inches x 12 inches

'arch-a-translucent': Specifies the Architectural A size translucent

  medium: 9 inches x 12 inches

'arch-b-white': Specifies the Architectural B size white medium: 12

  inches x 18 inches

'arch-b-transparent': Specifies the Architectural B size transparent

  medium: 12 inches x 18 inches

'arch-b-translucent': Specifies the Architectural B size translucent

  medium: 12 inches x 18 inches

'arch-c-white': Specifies the Architectural C size white medium: 18

  inches x 24 inches

'arch-c-transparent': Specifies the Architectural C size transparent

  medium: 18 inches x 24 inches

'arch-c-translucent': Specifies the Architectural C size translucent

  medium: 18 inches x 24 inches

'arch-d-white': Specifies the Architectural D size white medium: 24

  inches x 36 inches

'arch-d-transparent': Specifies the Architectural D size transparent

  medium: 24 inches x 36 inches

'arch-d-translucent': Specifies the Architectural D size translucent

  medium: 24 inches x 36 inches

'arch-e-white': Specifies the Architectural E size white medium: 36

  inches x 48 inches

'arch-e-transparent': Specifies the Architectural E size transparent

  medium: 36 inches x 48 inches

'arch-e-translucent': Specifies the Architectural E size translucent

  medium: 36 inches x 48 inches
 The following standard values are defined for American Architectural
 engineering media for devices that provide the "synchro-cut" feature
 (see section 14.1):

'arch-axsynchro-white': Specifies the roll paper having the width of

  the longer edge (12 inches) of the Architectural A size white
  medium and cuts synchronizing with data.

'arch-axsynchro-transparent': Specifies the roll paper having the

  width of the longer edge (12 inches) of the Architectural A size
  transparent medium and cuts synchronizing with data.

Hastings, et al. Standards Track [Page 195] RFC 2911 IPP/1.1: Model and Semantics September 2000

'arch-axsynchro-translucent': Specifies the roll paper having the

  width of the longer edge (12 inches) of the Architectural A size
  translucent medium and cuts synchronizing with data.

'arch-bxsynchro-white': Specifies the roll paper having the width of

  the longer edge (18 inches) of the Architectural B size white
  medium and cuts synchronizing with data.

'arch-bxsynchro-transparent': Specifies the roll paper having the

  width of the longer edge (18 inches) of the Architectural B size
  transparent medium and cuts synchronizing with data.

'arch-bxsynchro-translucent': Specifies the roll paper having the

  width of the longer edge (18 inches) of the Architectural B size
  translucent medium and cuts synchronizing with data.

'arch-cxsynchro-white': Specifies the roll paper having the width of

  the longer edge (24 inches) of the Architectural C size white
  medium and cuts synchronizing with data.

'arch-cxsynchro-transparent': Specifies the roll paper having the

  width of the longer edge (24 inches) of the Architectural C size
  transparent medium and cuts synchronizing with data.

'arch-cxsynchro-translucent': Specifies the roll paper having the

  width of the longer edge (24 inches) of the Architectural C size
  translucent medium and cuts synchronizing with data.

'arch-dxsynchro-white': Specifies the roll paper having the width of

  the longer edge (36 inches) of the Architectural D size white
  medium and cuts synchronizing with data.

'arch-dxsynchro-transparent': Specifies the roll paper having the

  width of the longer edge (36 inches) of the Architectural D size
  transparent medium and cuts synchronizing with data.

'arch-dxsynchro-translucent': Specifies the roll paper having the

  width of the longer edge (36 inches) of the Architectural D size
  translucent medium and cuts synchronizing with data.

'arch-exsynchro-white': Specifies the roll paper having the width of

  the longer edge (48 inches) of the Architectural E size white
  medium and cuts synchronizing with data.

'arch-exsynchro-transparent': Specifies the roll paper having the

  width of the longer edge (48 inches) of the Architectural E size
  transparent medium and cuts synchronizing with data.

'arch-exsynchro-translucent': Specifies the roll paper having the

  width of the longer edge (48 inches) of the Architectural E size
  translucent medium and cuts synchronizing with data.
 The following standard values are defined for Japanese and European
 Standard (i.e. ISO) engineering media, which are of a long fixed size
 [ASME-Y14.1M]:

'iso-a1x3-white': Specifies the ISO A1X3 white medium having the

    width of the longer edge (841 mm) of the ISO A1 medium

Hastings, et al. Standards Track [Page 196] RFC 2911 IPP/1.1: Model and Semantics September 2000

'iso-a1x3-transparent': Specifies the ISO A1X3 transparent medium

    having the width of the longer edge (841 mm) of the ISO A1
    medium

'iso-a1x3-translucent': Specifies the ISO A1X3 translucent medium

    having the width of the longer edge (841 mm) of the ISO A1
    medium

'iso-a1x4-white': Specifies the ISO A1X4 white medium having the

    width of the longer edge (841 mm) of the ISO A1 medium

'iso-a1x4-transparent': Specifies the ISO A1X4 transparent medium

    having the width of the longer edge (841 mm) of the ISO A1
    medium

'iso-a1x4- translucent': Specifies the ISO A1X4 translucent medium

    having the width of the longer edge (841 mm) of the ISO A1
    medium

'iso-a2x3-white': Specifies the ISO A2X3 white medium having the

    width of the longer edge (594 mm) of the ISO A2 medium

'iso-a2x3-transparent': Specifies the ISO A2X3 transparent medium

    having the width of the longer edge (594 mm) of the ISO A2
    medium

'iso-a2x3-translucent': Specifies the ISO A2X3 translucent medium

    having the width of the longer edge (594 mm) of the ISO A2
    medium

'iso-a2x4-white': Specifies the ISO A2X4 white medium having the

    width of the longer edge (594 mm) of the ISO A2 medium

'iso-a2x4-transparent': Specifies the ISO A2X4 transparent medium

    having the width of the longer edge (594 mm) of the ISO A2
    medium

'iso-a2x4-translucent': Specifies the ISO A2X4 translucent medium

    having the width of the longer edge (594 mm) of the ISO A2
    medium

'iso-a2x5-white': Specifies the ISO A2X5 white medium having the

    width of the longer edge (594 mm) of the ISO A2 medium

'iso-a2x5-transparent': Specifies the ISO A2X5 transparent medium

    having the width of the longer edge (594 mm) of the ISO A2
    medium

'iso-a2x5-translucent': Specifies the ISO A2X5 translucent medium

    having the width of the longer edge (594 mm) of the ISO A2
    medium

'iso-a3x3-white': Specifies the ISO A3X3 white medium having the

    width of the longer edge (420 mm) of the ISO A3 medium

'iso-a3x3-transparent': Specifies the ISO A3X3 transparent medium

    having the width of the longer edge (420 mm) of the ISO A3
    medium

'iso-a3x3-translucent': Specifies the ISO A3X3 translucent medium

    having the width of the longer edge (420 mm) of the ISO A3
    medium

'iso-a3x4-white': Specifies the ISO A3X4 white medium having the

    width of the longer edge (420 mm) of the ISO A3 medium

Hastings, et al. Standards Track [Page 197] RFC 2911 IPP/1.1: Model and Semantics September 2000

'iso-a3x4-transparent': Specifies the ISO A3X4 transparent medium

    having the width of the longer edge (420 mm) of the ISO A3
    medium

'iso-a3x4-translucent': Specifies the ISO A3X4 translucent medium

    having the width of the longer edge (420 mm) of the ISO A3
    medium

'iso-a3x5-white': Specifies the ISO A3X5 white medium having the

    width of the longer edge (420 mm) of the ISO A3 medium

'iso-a3x5-transparent': Specifies the ISO A3X5 transparent medium

    having the width of the longer edge (420 mm) of the ISO A3
    medium

'iso-a3x5-translucent': Specifies the ISO A3X5 translucent medium

    having the width of the longer edge (420 mm) of the ISO A3
    medium

'iso-a3x6-white': Specifies the ISO A3X6 white medium having the

    width of the longer edge (420 mm) of the ISO A3 medium

'iso-a3x6-transparent': Specifies the ISO A3X6 transparent medium

    having the width of the longer edge (420 mm) of the ISO A3
    medium

'iso-a3x6-translucent': Specifies the ISO A3X6 translucent medium

    having the width of the longer edge (420 mm) of the ISO A3
    medium

'iso-a3x7-white': Specifies the ISO A3X7 white medium having the

    width of the longer edge (420 mm) of the ISO A3 medium

'iso-a3x7-transparent': Specifies the ISO A3X7 transparent medium

    having the width of the longer edge (420 mm) of the ISO A3
    medium

'iso-a3x7-translucent: Specifies the ISO A3X7 translucent' medium having the width of the longer edge (420 mm) of the ISO A3 medium 'iso-a4x3-white': Specifies the ISO A4X3 white medium having the width of the longer edge (297 mm) of the ISO A4 medium 'iso-a4x3-transparent': Specifies the ISO A4X3 transparent medium having the width of the longer edge (297 mm) of the ISO A4 medium 'iso-a4x3-translucent: Specifies the ISO A4X3 translucent' medium

    having the width of the longer edge (297 mm) of the ISO A4
    medium

'iso-a4x4-white': Specifies the ISO A4X4 white medium having the

    width of the longer edge (297 mm) of the ISO A4 medium

'iso-a4x4-transparent': Specifies the ISO A4X4 transparent medium

    having the width of the longer edge (297 mm) of the ISO A4
    medium

'iso-a4x4-translucent': Specifies the ISO A4X4 translucent medium

    having the width of the longer edge (297 mm) of the ISO A4
    medium

'iso-a4x5-white': Specifies the ISO A4X5 white medium having the

    width of the longer edge (297 mm) of the ISO A4 medium

Hastings, et al. Standards Track [Page 198] RFC 2911 IPP/1.1: Model and Semantics September 2000

'iso-a4x5-transparent': Specifies the ISO A4X5 transparent medium

    having the width of the longer edge (297 mm) of the ISO A4
    medium

'iso-a4x5-translucent': Specifies the ISO A4X5 translucent medium

    having the width of the longer edge (297 mm) of the ISO A4
    medium

'iso-a4x6-white': Specifies the ISO A4X6 white medium having the

    width of the longer edge (297 mm) of the ISO A4 medium

'iso-a4x6-transparent': Specifies the ISO A4X6 transparent medium

    having the width of the longer edge (297 mm) of the ISO A4
    medium

'iso-a4x6-translucent': Specifies the ISO A4X6 translucent medium

    having the width of the longer edge (297 mm) of the ISO A4
    medium

'iso-a4x7-white': Specifies the ISO A4X7 white medium having the

    width of the longer edge (297 mm) of the ISO A4 medium

'iso-a4x7-transparent': Specifies the ISO A4X7 transparent medium

    having the width of the longer edge (297 mm) of the ISO A4
    medium

'iso-a4x7-translucent': Specifies the ISO A4X7 translucent medium

    having the width of the longer edge (297 mm) of the ISO A4
    medium

'iso-a4x8-white': Specifies the ISO A4X8 white medium having the

    width of the longer edge (297 mm) of the ISO A4 medium

'iso-a4x8-transparent': Specifies the ISO A4X8 transparent medium

    having the width of the longer edge (297 mm) of the ISO A4
    medium

'iso-a4x8-translucent': Specifies the ISO A4X8 translucent medium

    having the width of the longer edge (297 mm) of the ISO A4
    medium

'iso-a4x9-white': Specifies the ISO A4X9 white medium having the

    width of the longer edge (297 mm) of the ISO A4 medium

'iso-a4x9-transparent': Specifies the ISO A4X9 transparent medium

    having the width of the longer edge (297 mm) of the ISO A4
    medium

'iso-a4x9-translucent': Specifies the ISO A4X9 translucent medium

    having the width of the longer edge (297 mm) of the ISO A4
    medium
 The following standard values are defined for Japanese and European
 Standard (i.e. ISO) engineering media, which are either a long fixed
 size [ASME-Y14.1M] or roll feed, for devices that provide the
 "synchro-cut" feature (see section 14.1):

'iso-a0xsynchro-white': Specifies the paper having the width of the

    longer edge (1189 mm) of the ISO A0 white medium and cuts
    synchronizing with data.

Hastings, et al. Standards Track [Page 199] RFC 2911 IPP/1.1: Model and Semantics September 2000

'iso-a0xsynchro-transparent': Specifies the paper having the width of

    the longer edge (1189 mm) of the ISO A0 transparent medium and
    cuts synchronizing with data.

'iso-a0xsynchro-translucent': Specifies the paper having the width of

    the longer edge (1189 mm) of the ISO A0 translucent medium and
    cuts synchronizing with data.

'iso-a1xsynchro-white': Specifies the paper having the width of the

    longer edge (841 mm) of the ISO A1 white medium and cuts
    synchronizing with data.

'iso-a1xsynchro-transparent': Specifies the paper having the width of

    the longer edge (841 mm) of the ISO A1 transparent medium and
    cuts synchronizing with data.

'iso-a1xsynchro-translucent': Specifies the paper having the width of

    the longer edge (841 mm) of the ISO A1 translucent medium and
    cuts synchronizing with data.

'iso-a2xsynchro-white': Specifies the paper having the width of the

    longer edge (594 mm) of the ISO A2 white medium and cuts
    synchronizing with data.

'iso-a2xsynchro-transparent': Specifies the paper having the width of

    the longer edge (594 mm) of the ISO A2 transparent medium and
    cuts synchronizing with data.

'iso-a2xsynchro-translucent': Specifies the paper having the width of

    the longer edge (594 mm) of the ISO A2 translucent medium and
    cuts synchronizing with data.

'iso-a3xsynchro-white': Specifies the paper having the width of the

    longer edge (420 mm) of the ISO A3 white medium and cuts
    synchronizing with data.

'iso-a3xsynchro-transparent': Specifies the paper having the width of

    the longer edge (420 mm) of the ISO A3 transparent medium and
    cuts synchronizing with data.

'iso-a3xsynchro-translucent': Specifies the paper having the width of

    the longer edge (420 mm) of the ISO A3 translucent medium and
    cuts synchronizing with data.

'iso-a4xsynchro-white': Specifies the paper having the width of the

    longer edge (297 mm) of the ISO A4 white medium and cuts
    synchronizing with data.

'iso-a4xsynchro-transparent': Specifies the paper having the width of

    the longer edge (297 mm) of the ISO A4 transparent medium and
    cuts synchronizing with data.

'iso-a4xsynchro-translucent': Specifies the paper having the width of

    the longer edge (297 mm) of the ISO A4 transparent medium and
    cuts synchronizing with data.
 The following standard values are defined for American Standard (i.e.
 ANSI) engineering media, American Architectural engineering media,
 and Japanese and European Standard (i.e. ISO) engineering media,

Hastings, et al. Standards Track [Page 200] RFC 2911 IPP/1.1: Model and Semantics September 2000

 which are either a long fixed size [ASME-Y14.1M] or roll feed, for
 devices that provide the "synchro-cut" feature and/or the "auto-
 select" feature (see section 14.1):

'auto-white': Specifies that the printer selects the white medium

    with the appropriate fixed size (e.g. a1, a2, etc.) or data-
    synchro size, and the selection is implementation-defined.

'auto-transparent': Specifies that the printer selects the

    transparent medium with the appropriate fixed size (e.g. a1, a2,
    etc.) or data-synchro size, and the selection is implementation-
    defined.

'auto-translucent': Specifies that the printer selects the

    translucent medium with the appropriate fixed size (e.g. a1, a2,
    etc.) or data-synchro size, and the selection is implementation-
    defined.

'auto-fixed-size-white': Specifies that the printer selects the white

    medium with the appropriate fixed size (e.g. a1, a2, etc.) or
    the appropriate long fixed size listed above.

'auto-fixed-size-transparent': Specifies that the printer selects the

    transparent medium with the appropriate fixed size (e.g. a1, a2,
    etc.) or the appropriate long fixed size listed above.

'auto-fixed-size-translucent': Specifies that the printer selects the

    translucent medium with the appropriate fixed size (e.g. a1, a2,
    etc.) or the appropriate long fixed size listed above.

'auto-synchro-white': Specifies that the printer selects the white

    paper with the appropriate width and cuts it synchronizing with
    data.

'auto-synchro-transparent': Specifies that the printer selects the

    transparent paper with the appropriate width and cuts it
    synchronizing with data.

'auto-synchro-translucent': Specifies that the printer selects the

    translucent paper with the appropriate width and cuts it
    synchronizing with data.
 The following standard values are defined for input-trays (from ISO
 DPA and the Printer MIB):
  'top': The top input tray in the printer.
  'middle': The middle input tray in the printer.
  'bottom': The bottom input tray in the printer.
  'envelope': The envelope input tray in the printer.
  'manual': The manual feed input tray in the printer.
  'large-capacity': The large capacity input tray in the printer.
  'main': The main input tray
  'side': The side input tray

Hastings, et al. Standards Track [Page 201] RFC 2911 IPP/1.1: Model and Semantics September 2000

 The following standard values are defined for media sizes (from ISO
 DPA):

'iso-a0': Specifies the ISO A0 size: 841 mm by 1189 mm as defined in

  ISO 216

'iso-a1': Specifies the ISO A1 size: 594 mm by 841 mm as defined in

  ISO 216

'iso-a2': Specifies the ISO A2 size: 420 mm by 594 mm as defined in

  ISO 216

'iso-a3': Specifies the ISO A3 size: 297 mm by 420 mm as defined in

  ISO 216

'iso-a4': Specifies the ISO A4 size: 210 mm by 297 mm as defined in

  ISO 216

'iso-a5': Specifies the ISO A5 size: 148 mm by 210 mm as defined in

  ISO 216

'iso-a6': Specifies the ISO A6 size: 105 mm by 148 mm as defined in

  ISO 216

'iso-a7': Specifies the ISO A7 size: 74 mm by 105 mm as defined in

  ISO 216

'iso-a8': Specifies the ISO A8 size: 52 mm by 74 mm as defined in ISO

  216

'iso-a9': Specifies the ISO A9 size: 37 mm by 52 mm as defined in ISO

  216

'iso-a10': Specifies the ISO A10 size: 26 mm by 37 mm as defined in

  ISO 216

'iso-b0': Specifies the ISO B0 size: 1000 mm by 1414 mm as defined in

  ISO 216

'iso-b1': Specifies the ISO B1 size: 707 mm by 1000 mm as defined in

  ISO 216

'iso-b2': Specifies the ISO B2 size: 500 mm by 707 mm as defined in

  ISO 216

'iso-b3': Specifies the ISO B3 size: 353 mm by 500 mm as defined in

  ISO 216

'iso-b4': Specifies the ISO B4 size: 250 mm by 353 mm as defined in

  ISO 216

'iso-b5': Specifies the ISO B5 size: 176 mm by 250 mm as defined in

  ISO 216

'iso-b6': Specifies the ISO B6 size: 125 mm by 176 mm as defined in

  ISO 216

'iso-b7': Specifies the ISO B7 size: 88 mm by 125 mm as defined in

  ISO 216

'iso-b8': Specifies the ISO B8 size: 62 mm by 88 mm as defined in ISO

  216

'iso-b9': Specifies the ISO B9 size: 44 mm by 62 mm as defined in ISO

  216

'iso-b10': Specifies the ISO B10 size: 31 mm by 44 mm as defined in

  ISO 216

Hastings, et al. Standards Track [Page 202] RFC 2911 IPP/1.1: Model and Semantics September 2000

'na-letter': Specifies the North American letter size: 8.5 inches by

  11 inches

'na-legal': Specifies the North American legal size: 8.5 inches by 14

  inches

'na-8x10': Specifies the North American 8 inches by 10 inches 'na-5x7': Specifies the North American 5 inches by 7 inches 'executive': Specifies the executive size (7.25 X 10.5 in) 'folio': Specifies the folio size (8.5 X 13 in) 'invoice': Specifies the invoice size (5.5 X 8.5 in) 'ledger': Specifies the ledger size (11 X 17 in) 'quarto': Specifies the quarto size (8.5 X 10.83 in) 'iso-c3': Specifies the ISO C3 size: 324 mm by 458 mm as defined in

  ISO 269

'iso-c4': Specifies the ISO C4 size: 229 mm by 324 mm as defined in

  ISO 269

'iso-c5': Specifies the ISO C5 size: 162 mm by 229 mm as defined in

  ISO 269

'iso-c6': Specifies the ISO C6 size: 114 mm by 162 mm as defined in

  ISO 269

'iso-designated-long': Specifies the ISO Designated Long size: 110 mm

  by 220 mm as defined in ISO 269

'na-10x13-envelope': Specifies the North American 10x13 size: 10

  inches by 13 inches

'na-9x12-envelope': Specifies the North American 9x12 size: 9 inches

  by 12 inches

'na-number-10-envelope': Specifies the North American number 10

  business envelope size: 4.125 inches by 9.5 inches

'na-7x9-envelope': Specifies the North American 7x9 inch envelope

  size

'na-9x11-envelope': Specifies the North American 9x11 inch envelope

  size

'na-10x14-envelope': Specifies the North American 10x14 inch envelope

  size

'na-number-9-envelope': Specifies the North American number 9

  business envelope size

'na-6x9-envelope': Specifies the North American 6x9 envelope size 'na-10x15-envelope': Specifies the North American 10x15 envelope size 'monarch-envelope': Specifies the Monarch envelope size (3.87 x 7.5

  in)

'jis-b0': Specifies the JIS B0 size: 1030mm x 1456mm 'jis-b1': Specifies the JIS B1 size: 728mm x 1030mm 'jis-b2': Specifies the JIS B2 size: 515mm x 728mm 'jis-b3': Specifies the JIS B3 size: 364mm x 515mm 'jis-b4': Specifies the JIS B4 size: 257mm x 364mm 'jis-b5': Specifies the JIS B5 size: 182mm x 257mm 'jis-b6': Specifies the JIS B6 size: 128mm x 182mm 'jis-b7': Specifies the JIS B7 size: 91mm x 128mm 'jis-b8': Specifies the JIS B8 size: 64mm x 91mm

Hastings, et al. Standards Track [Page 203] RFC 2911 IPP/1.1: Model and Semantics September 2000

'jis-b9': Specifies the JIS B9 size: 45mm x 64mm 'jis-b10': Specifies the JIS B10 size: 32mm x 45mm

 The following standard values are defined for American Standard (i.e.
 ANSI) engineering media sizes:
  'a': Specifies the engineering ANSI A size medium: 8.5 inches x 11
     inches
  'b': Specifies the engineering ANSI B size medium: 11 inches x 17
     inches
  'c': Specifies the engineering ANSI C size medium: 17 inches x 22
     inches
  'd': Specifies the engineering ANSI D size medium: 22 inches x 34
     inches
  'e': Specifies the engineering ANSI E size medium: 34 inches x 44
     inches
 The following standard values are defined for American Architectural
 engineering media sizes:
  'arch-a': Specifies the Architectural A size medium: 9 inches x 12
     inches
  'arch-b': Specifies the Architectural B size medium: 12 inches x 18
     inches
  'arch-c': Specifies the Architectural C size medium: 18 inches x 24
     inches
  'arch-d': Specifies the Architectural D size medium: 24 inches x 36
     inches
  'arch-e': Specifies the Architectural E size medium: 36 inches x 48
     inches

Hastings, et al. Standards Track [Page 204] RFC 2911 IPP/1.1: Model and Semantics September 2000

14.1. Examples

 Below are examples to supplement the engineering media value
 definitions.
 Example 1:  "Synchro-Cut", a device cutting the roll paper in
 synchronization with the data
   data height:          A1 height
   data width (shaded):  A1 width < data width < (A1 width) x 2
   specified value:      'iso-a1xsynchro-white'
             |                    |
             |<--- data width --->|
             |                    |
             |              |     |        |
             |<- A1 width ->|<- A1 width ->|
             |              |     |        |
   cross  ^  |              |     |        |
    feed  |  +--------------------------------------------/

direction | ||/| | ^ / | ||/| | | /

          |  |//////////////|/////|        |     |     /
          |  |//////////////|/////|        |     |     \

←———-+- ||/| | A1 \ roll feed | ||/| | height \ paper direction ||/| | | \ ||/| | | /

             |//////////////|/////|        |     v       /
             +------------------------------------------/
                                  |
                                  |
                                  |<------ CUT HERE (to synchronize
                                  |                with data width)
                                  |

Hastings, et al. Standards Track [Page 205] RFC 2911 IPP/1.1: Model and Semantics September 2000

 Example 2: "Auto-Cut", a device cutting the roll paper at multiples
 of fixed-size media width
   data height:          A1 height
   data width (shaded):  A1 width < data width < (A1 width) x 2
   specified value:      'auto-fixed-size-white'
               |                    |
               |<--- data width --->|
               |                    |
               |              |     |        |
               |<- A1 width ->|<- A1 width ->|
               |              |     |        |
   cross  ^    |              |     |        |
    feed  |    +--------------------------------------------/

direction | ||/| | ^ / | ||/| | | /

          |    |//////////////|/////|        |     |     /
          |    |//////////////|/////|        |     |     \

←———-+- ||/| | A1 \ roll feed | ||/| | height \ paper direction ||/| | | \ ||/| | | /

               |//////////////|/////|        |     v       /
               +------------------------------------------/
                                             |
                                             |
                                             |<--- CUT HERE
                                             |      (to synchronize
                                             |       with data width)

Hastings, et al. Standards Track [Page 206] RFC 2911 IPP/1.1: Model and Semantics September 2000

 Example 3:  the 'iso-a4x4-white' fixed size paper
   paper height:         A4 height
   paper width:          (A4 width) x 4
   specified value:      'iso-a4x4-white'
 |              |              |              |              |
 |<- A4 width ->|<- A4 width ->|<- A4 width ->|<- A4 width ->|
 |              |              |              |              |
 |              |              |              |              |
 +-----------------------------------------------------------+
 |       ^      |              |              |              |
 |       |      |              |              |              |
 |       |      |              |              |              |
 |      A4      |              |              |              |
 |    height    |              |              |              |
 |       |      |              |              |              |
 |       |      |              |              |              |
 |       |      |              |              |              |
 |       v      |              |              |              |
 +-----------------------------------------------------------+

Hastings, et al. Standards Track [Page 207] RFC 2911 IPP/1.1: Model and Semantics September 2000

 Example 4: "Synchro-Cut", a device cutting the fixed size paper in
 synchronization with the data
   data height:          A4 height
   data width (shaded):  (A4 width) x 2 < data width < (A4 width) x 3
   specified value:      'iso-a4xsynchro-white'
                  |                                   |
                  |<---------- data width ----------->|
                  |                                   |
                  |              |              |     |        |
                  |<- A4 width ->|<- A4 width ->|<- A4 width ->|
                  |              |              |     |        |
      cross  ^    |              |              |     |        |
       feed  |    +--------------------------------------------+
  direction  |    |//////////////|//////////////|/////|    ^   |
             |    |//////////////|//////////////|/////|    |   |
             |    |//////////////|//////////////|/////|    |   |
             |    |//////////////|//////////////|/////|    |   |
 <-----------+-   |//////////////|//////////////|/////|   A4   |
 feed        |    |//////////////|//////////////|/////| height |
 direction        |//////////////|//////////////|/////|    |   |
                  |//////////////|//////////////|/////|    |   |
                  |//////////////|//////////////|/////|    v   |
                  +--------------------------------------------+
                                                      |
                                        CUT HERE ---->|
                                  (to synchronize     |
                                  with data width)    |

15. APPENDIX D: Processing IPP Attributes

 When submitting a print job to a Printer object, the IPP model allows
 a client to supply operation and Job Template attributes along with
 the document data.  These Job Template attributes in the create
 request affect the rendering, production and finishing of the
 documents in the job.  Similar types of instructions may also be
 contained in the document to be printed, that is, embedded within the
 print data itself.  In addition, the Printer has a set of attributes
 that describe what rendering and finishing options which are
 supported by that Printer.  This model, which allows for flexibility
 and power, also introduces the potential that at job submission time,
 these client-supplied attributes may conflict with either:
  1. what the implementation is capable of realizing (i.e., what the

Printer supports), as well as

  1. the instructions embedded within the print data itself.

Hastings, et al. Standards Track [Page 208] RFC 2911 IPP/1.1: Model and Semantics September 2000

 The following sections describe how these two types of conflicts are
 handled in the IPP model.

15.1 Fidelity

 If there is a conflict between what the client requests and what a
 Printer object supports, the client may request one of two possible
 conflict handling mechanisms:
    1) either reject the job since the job can not be processed
       exactly as specified, or
    2) allow the Printer to make any changes necessary to proceed with
       processing the Job the best it can.
 In the first case the client is indicating to the Printer object:
 "Print the job exactly as specified with no exceptions, and if that
 can't be done, don't even bother printing the job at all." In the
 second case, the client is indicating to the Printer object: "It is
 more important to make sure the job is printed rather than be
 processed exactly as specified; just make sure the job is printed
 even if some client-supplied attributes need to be changed or
 ignored."
 The IPP model accounts for this situation by introducing an "ipp-
 attribute-fidelity" attribute.
 In a create request, "ipp-attribute-fidelity" is a boolean operation
 attribute that is OPTIONALLY supplied by the client.  The value
 'true' indicates that total fidelity to client supplied Job Template
 attributes and values is required.  The client is requesting that the
 Job be printed exactly as specified, and if that is not possible then
 the job MUST be rejected rather than processed incorrectly.  The
 value 'false' indicates that a reasonable attempt to print the Job is
 acceptable.  If a Printer does not support some of the client
 supplied Job Template attributes or values, the Printer MUST ignore
 them or substitute any supported value for unsupported values,
 respectively.  The Printer may choose to substitute the default value
 associated with that attribute, or use some other supported value
 that is similar to the unsupported requested value.  For example, if
 a client supplies a "media" value of 'na-letter', the Printer may
 choose to substitute 'iso-a4' rather than a default value of
 'envelope'. If the client does not supply the "ipp-attribute-
 fidelity" attribute, the Printer assumes a value of 'false'.
 Each Printer implementation MUST support both types of "fidelity"
 printing (that is whether the client supplies a value of 'true' or
 'false'):

Hastings, et al. Standards Track [Page 209] RFC 2911 IPP/1.1: Model and Semantics September 2000

  1. If the client supplies 'false' or does not supply the attribute,

the Printer object MUST always accept the request by ignoring

      unsupported Job Template attributes and by substituting
      unsupported values of supported Job Template attributes with
      supported values.
    - If the client supplies 'true', the Printer object MUST reject
      the request if the client supplies unsupported Job Template
      attributes.
 Since a client can always query a Printer to find out exactly what is
 and is not supported, "ipp-attribute-fidelity" set to 'false' is
 useful when:
    1) The End-User uses a command line interface to request
       attributes that might not be supported.
    2) In a GUI context, if the End User expects the job might be
       moved to another printer and prefers a sub-optimal result to
       nothing at all.
    3) The End User just wants something reasonable in lieu of nothing
       at all.

15.2 Page Description Language (PDL) Override

 If there is a conflict between the value of an IPP Job Template
 attribute and a corresponding instruction in the document data, the
 value of the IPP attribute SHOULD take precedence over the document
 instruction.  Consider the case where a previously formatted file of
 document data is sent to an IPP Printer.  In this case, if the client
 supplies any attributes at job submission time, the client desires
 that those attributes override the embedded instructions.  Consider
 the case were a previously formatted document has embedded in it
 commands to load 'iso-a4' media.  However, the document is passed to
 an end user that only has access to a printer with 'na-letter' media
 loaded.  That end user most likely wants to submit that document to
 an IPP Printer with the "media" Job Template attribute set to 'na-
 letter'.  The job submission attribute should take precedence over
 the embedded PDL instruction.  However, until companies that supply
 document data interpreters allow a way for external IPP attributes to
 take precedence over embedded job production instructions, a Printer
 might not be able to support the semantics that IPP attributes
 override the embedded instructions.
 The IPP model accounts for this situation by introducing a "pdl-
 override-supported" attribute that describes the Printer objects
 capabilities to override instructions embedded in the PDL data
 stream.  The value of the "pdl-override-supported" attribute is
 configured by means outside the scope of this IPP/1.1 document.

Hastings, et al. Standards Track [Page 210] RFC 2911 IPP/1.1: Model and Semantics September 2000

 This REQUIRED Printer attribute takes on the following values:
  1. 'attempted': This value indicates that the Printer object

attempts to make the IPP attribute values take precedence over

      embedded instructions in the document data, however there is no
      guarantee.
    - 'not-attempted': This value indicates that the Printer object
      makes no attempt to make the IPP attribute values take
      precedence over embedded instructions in the document data.
 At job processing time, an implementation that supports the value of
 'attempted' might do one of several different actions:
    1) Generate an output device specific command sequence to realize
       the feature represented by the IPP attribute value.
    2) Parse the document data itself and replace the conflicting
       embedded instruction with a new embedded instruction that
       matches the intent of the IPP attribute value.
    3) Indicate to the Printer that external supplied attributes take
       precedence over embedded instructions and then pass the
       external IPP attribute values to the document data interpreter.
    4) Anything else that allows for the semantics that IPP attributes
       override embedded document data instructions.
 Since 'attempted' does not offer any type of guarantee, even though a
 given Printer object might not do a very "good" job of attempting to
 ensure that IPP attributes take a higher precedence over instructions
 embedded in the document data, it would still be a conforming
 implementation.
 At job processing time, an implementation that supports the value of
 'not-attempted' might do one of the following actions:
    1) Simply pre-pend the document data with the PDL instruction that
       corresponds to the client-supplied PDL attribute, such that if
       the document data also has the same PDL instruction, it will
       override what the Printer object pre-pended.  In other words,
       this implementation is using the same implementation semantics
       for the client-supplied IPP attributes as for the Printer
       object defaults.
    2) Parse the document data and replace the conflicting embedded
       instruction with a new embedded instruction that approximates,
       but does not match, the semantic intent of the IPP attribute
       value.
 Note:  The "ipp-attribute-fidelity" attribute applies to the
 Printer's ability to either accept or reject other unsupported Job

Hastings, et al. Standards Track [Page 211] RFC 2911 IPP/1.1: Model and Semantics September 2000

 Template attributes.  In other words, if "ipp-attribute-fidelity" is
 set to 'true', a Job is accepted if and only if the client supplied
 Job Template attributes and values are supported by the Printer.
 Whether these attributes actually affect the processing of the Job
 when the document data contains embedded instructions depends on the
 ability of the Printer to override the instructions embedded in the
 document data with the semantics of the IPP attributes.  If the
 document data attributes can be overridden ("pdl-override-supported"
 set to 'attempted'), the Printer makes an attempt to use the IPP
 attributes when processing the Job. If the document data attributes
 can not be overridden ("pdl-override-supported" set to 'not-
 attempted'), the Printer makes no attempt to override the embedded
 document data instructions with the IPP attributes when processing
 the Job, and hence, the IPP attributes may fail to affect the Job
 processing and output when the corresponding instruction is embedded
 in the document data.

15.3 Using Job Template Attributes During Document Processing.

 The Printer object uses some of the Job object's Job Template
 attributes during the processing of the document data associated with
 that job.  These include, but are not limited to, "orientation-
 requested", "number-up", "sides", "media", and "copies".  The
 processing of each document in a Job Object MUST follow the steps
 below. These steps are intended only to identify when and how
 attributes are to be used in processing document data and any
 alternative steps that accomplishes the same effect can be used to
 implement this specification document.
    1. Using the client supplied "document-format" attribute or some
       form of document format detection algorithm (if the value of
       "document-format" is not specific enough), determine whether or
       not the document data has already been formatted for printing.
       If the document data has been formatted, then go to step 2.
       Otherwise, the document data MUST be formatted. The formatting
       detection algorithm is implementation defined and is not
       specified by this document.  The formatting of the document
       data uses the "orientation-requested" attribute to determine
       how the formatted print data should be placed on a print-stream
       page, see section 4.2.10 for the details.
    2. The document data is in the form of a print-stream in a known
       media type. The "page-ranges" attribute is used to select, as
       specified in section 4.2.7, a sub-sequence of the pages in the
       print-stream that are to be processed and images.
    3. The input to this step is a sequence of print-stream pages.
       This step is controlled by the "number-up" attribute. If the

Hastings, et al. Standards Track [Page 212] RFC 2911 IPP/1.1: Model and Semantics September 2000

       value of "number-up" is N, then during the processing of the
       print-stream pages, each N print-stream pages are positioned,
       as specified in section 4.2.9, to create a single impression.
       If a given document does not have N more print-stream pages,
       then the completion of the impression is controlled by the
       "multiple-document-handling" attribute as described in section
       4.2.4; when the value of this attribute is 'single-document' or
       'single-document-new-sheet', the print-stream pages of document
       data from subsequent documents is used to complete the
       impression.
       The size(scaling), position(translation) and rotation of the
       print-stream pages on the impression is implementation defined.
       Note that during this process the print-stream pages may be
       rendered to a form suitable for placing on the impression; this
       rendering is controlled by the values of the "printer-
       resolution" and "print-quality" attributes as described in
       sections 4.2.12 and 4.2.13. In the case N=1, the impression is
       nearly the same as the print-stream page; the differences would
       only be in the size, position and rotation of the print-stream
       page and/or any decoration, such as a frame to the page, that
       is added by the implementation.
    4. The collection of impressions is placed, in sequence, onto
       sides of the media sheets. This placement is controlled by the
       "sides" attribute and the orientation of the print-stream page,
       as described in section 4.2.8. The orientation of the print-
       stream pages affects the orientation of the impression; for
       example, if "number-up" equals 2, then, typically, two portrait
       print-stream pages become one landscape impression. Note that
       the placement of impressions onto media sheets is also
       controlled by the "multiple-document-handling" attribute as
       described in section 4.2.4.
    5. The "copies" and "multiple-document-handling" attributes are
       used to determine how many copies of each media instance are
       created and in what order. See sections 4.2.5 and 4.2.4 for the
       details.
    6. When the correct number of copies are created, the media
       instances are finished according to the values of the
       "finishings" attribute as described in 4.2.6. Note that
       sometimes finishing operations may require manual intervention
       to perform the finishing operations on the copies, especially
       uncollated copies. This document allows any or all of the
       processing steps to be performed automatically or manually at
       the discretion of the Printer object.

Hastings, et al. Standards Track [Page 213] RFC 2911 IPP/1.1: Model and Semantics September 2000

16. APPENDIX E: Generic Directory Schema

 This section defines a generic schema for an entry in a directory
 service.  A directory service is a means by which service users can
 locate service providers.  In IPP environments, this means that IPP
 Printers can be registered (either automatically or with the help of
 an administrator) as entries of type printer in the directory using
 an implementation specific mechanism such as entry attributes, entry
 type fields, specific branches, etc.  Directory clients can search or
 browse for entries of type printer.  Clients use the directory
 service to find entries based on naming, organizational contexts, or
 filtered searches on attribute values of entries.  For example, a
 client can find all printers in the "Local Department" context.
 Authentication and authorization are also often part of a directory
 service so that an administrator can place limits on end users so
 that they are only allowed to find entries to which they have certain
 access rights.  IPP itself does not require any specific directory
 service protocol or provider.
 Note: Some directory implementations allow for the notion of
 "aliasing".  That is, one directory entry object can appear as
 multiple directory entry object with different names for each object.
 In each case, each alias refers to the same directory entry object
 which refers to a single IPP Printer object.
 The generic schema is a subset of IPP Printer Job Template and
 Printer Description attributes (sections 4.2 and 4.4).  These
 attributes are identified as either RECOMMENDED or OPTIONAL for the
 directory entry itself.  This conformance labeling is NOT the same
 conformance labeling applied to the attributes of IPP Printers
 objects.  The conformance labeling in this Appendix is intended to
 apply to directory templates and to IPP Printer implementations that
 subscribe by adding one or more entries to a directory.  RECOMMENDED
 attributes SHOULD be associated with each directory entry.  OPTIONAL
 attributes MAY be associated with the directory entry (if known or
 supported).  In addition, all directory entry attributes SHOULD
 reflect the current attribute values for the corresponding Printer
 object.
 The names of attributes in directory schema and entries SHOULD be the
 same as the IPP Printer attribute names as shown, as much as
 possible.
 In order to bridge between the directory service and the IPP Printer
 object, one of the RECOMMENDED directory entry attributes is the
 Printer object's "printer-uri-supported" attribute.  The directory
 client queries the "printer-uri-supported" attribute (or its
 equivalent) in the directory entry and then the IPP client addresses

Hastings, et al. Standards Track [Page 214] RFC 2911 IPP/1.1: Model and Semantics September 2000

 the IPP Printer object using one of its URIs.  The "uri-security-
 supported" attribute identifies the protocol (if any) used to secure
 a channel.
 The following attributes define the generic schema for directory
 entries of type PRINTER:
   printer-uri-supported              RECOMMENDED    Section 4.4.1
   uri-authentication-supported       RECOMMENDED    Section 4.4.2
   uri-security-supported             RECOMMENDED    Section 4.4.3
   printer-name                       RECOMMENDED    Section 4.4.4
   printer-location                   RECOMMENDED    Section 4.4.5
   printer-info                       OPTIONAL       Section 4.4.6
   printer-more-info                  OPTIONAL       Section 4.4.7
   printer-make-and-model             RECOMMENDED    Section 4.4.9
   ipp-versions-supported             RECOMMENDED    Section 4.4.14
   multiple-document-jobs-supported   OPTIONAL       Section 4.4.16
   charset-supported                  OPTIONAL       Section 4.4.18
   generated-natural-language-
      supported                       OPTIONAL       Section 4.4.20
   document-format-supported          RECOMMENDED    Section 4.4.22
   color-supported                    RECOMMENDED    Section 4.4.26
   compression-supported              RECOMMENDED    Section 4.4.32
   pages-per-minute                   OPTIONAL       Section 4.4.36
   pages-per-minute-color             OPTIONAL       Section 4.4.37
   finishings-supported               OPTIONAL       Section 4.2.6
   number-up-supported                OPTIONAL       Section 4.2.7
   sides-supported                    RECOMMENDED    Section 4.2.8
   media-supported                    RECOMMENDED    Section 4.2.11
   printer-resolution-supported       OPTIONAL       Section 4.2.12
   print-quality-supported            OPTIONAL       Section 4.2.13

17. APPENDIX F: Differences between the IPP/1.0 and IPP/1.1 "Model and

  Semantics" Documents
 This Appendix is divided into two lists that summarize the
 differences between IPP/1.1 (this document) and IPP/1.0 [RFC2566].
 The section numbers refer to the numbers in this document which in
 some cases have changed from RFC 2566.  When a change affects
 multiple sections, the item is listed once in the order of the first
 section affected and the remaining affected section numbers are
 indicated.

Hastings, et al. Standards Track [Page 215] RFC 2911 IPP/1.1: Model and Semantics September 2000

 The first list contains extensions and clarifications and the second
 list contains changes in semantics or conformance.  However, client
 and IPP object implementations of IPP/1.0 MAY implement any of the
 extensions and clarifications in this document.
 The following extensions and clarifications have been incorporated
 into this document:
    1.  Section 2.1 - clarified that the term "client" can be either
        contained in software controlled by an end user or a part of a
        print server that controls devices.
    2.  Section 2 - clarified that the term "IPP object" and "Printer
        object" can either be embedded in a device object or part of a
        print server that accepts IPP requests.
    3.  Section 2.4 - added the description of the new "uri-
        authentication-supported" Printer Description attribute.
    4.  Section 3.1.3, 3.1.6, 3.2.5.2, and 3.2.6.2 - clarified the
        error handling for operation attributes that have their own
        status code.
    5.  Section 3.1.3 - clarified that multiple occurrences of the
        same attribute in an attribute group is mal-formed.  An IPP
        Printer MAY reject the request or choose one of the
        attributes.
    6.  Section 3.1.6 - reorganized this section into sub-sections to
        separately describe "status-code", "status-message",
        "detailed-status-message", and "document-access-error"
        attributes.
    7.  Section 3.1.6.1 - clarified the error status codes and their
        relationship to operation attributes.
    8.  Section 3.1.6.3 - Added the OPTIONAL "detailed-status-message
        (text(MAX))" operation attribute to provide additional more
        detailed information about a response.
    9.  Section 3.1.6.4 and 3.2.2 - Added the OPTIONAL "document-
        access-error (text(MAX))" operation attribute for use with
        Print-URI and Send-URI responses.
    10. Sections 3.1.7 - Added this new section to clarify returning
        Unsupported Attributes for all operations, including only
        returning attributes that were in the request.  Moved the text
        from section 3.2.1.2 Unsupported Attributes to this section.
    11. Sections 3.1.7 and 4.1 - clarified the encoding of the "out-
        of-band" 'unsupported' and 'unknown' values.
    12. Section 3.1.8 - clarified that only the version number
        parameter will be carried forward into future major or minor
        versions of the protocol.
    13. Section 3.1.8 - relaxed the requirements to increment the
        major version number in future versions of the Model and
        Semantics document.

Hastings, et al. Standards Track [Page 216] RFC 2911 IPP/1.1: Model and Semantics September 2000

    14. Section 3.1.9, and 3.2.5 - added the 'processing' state to the
        list of job states that a job can be in after a Create-Job
        operation.
    15. Section 3.1.9 - clarified that a non-spooling Printer MAY
        accept zero or more subsequent jobs while processing a job and
        flow control them down.  Subsequent create requests are
        rejected with the 'server-error-busy' error status.
    16. Section 3.2.1.1 - clarified the validation of the
        "compression" operation attribute and its relationship to the
        validation of the "document-format" attribute and returning
        Unsupported Attributes.
    17. Sections 3.2.1.1, 4.3.8, 13.1.4.16, and 13.1.4.17 - added the
        'client-error-compression-not-supported', 'client-error-
        compression-error' status codes and the 'unsupported-
        compression' and 'compression-error' job-state-reasons.
    18. Sections 3.2.1.1 and 4.3.8 - added 'unsupported-document-
        format' and 'document-format-error' job-state-reasons.
    19. Sections 3.2.2, 4.3.8 and 13.1.4.19 - added 'client-error-
        document-access-error' status code and 'document-access-error'
        job state reason.
    20. Section 3.2.5.2 and 3.2.6.2 - clarified that the Unsupported
        Attributes group MUST NOT include attributes not requested in
        the Get-Printer-Attributes request.
    21. Section 3.2.6 - clarified that "limit" takes precedence over
        "which-jobs" and "my-jobs'.
    22. Section 3.2.6.2 - clarified that Get-Jobs returns
        'successful-ok' when no jobs to return.
    23. Sections 3.2.7, 3.2.8, and 3.2.9 - added the OPTIONAL Pause-
        Printer, Resume-Printer, and Purge-Jobs operations
    24. Section 3.3.1  - clarified that the authorization required for
        a Send-Document request MUST be the same user as the Create-
        Job or an operator.
    25. Section 3.3.1.1 - clarified that a Create-Job Send-Document
        with "last-document" = 'true' and no data is not an error; its
        a job with no documents.
    26. Sections 3.3.5, 3.3.6, and 3.3.7 - added the OPTIONAL Hold-
        Job, Release-Job, and Restart-Job operations.  Clarified the
        Restart-Job operation so that the Printer MUST re-fetch any
        documents passed by-reference (Print-URI or Send-URI).
    27. Section 4.1 - clarified that the encoding of the out-of-band
        values are specified in the Encoding and Transport" document.
    28. Section 4.1 - Clarified that the requirement that clients MUST
        NOT send "out-of-band" values in requests applies only to
        operations defined in this document.  Other operations are
        allowed to define "out-of-band" values that clients can
        supply.

Hastings, et al. Standards Track [Page 217] RFC 2911 IPP/1.1: Model and Semantics September 2000

    29. Sections 4.1.1 and 4.1.2 - clarified that the maximum 'text'
        and 'name' values of 1023 and 255 are for the
        'textWithoutLanguage' portion of the 'textWithLanguage' form,
        so that the maximum number of octets for the actual text and
        name data is the same for the without and with language forms;
        the 'naturalLanguage' part is in addition.
    30. Section 4.1.9 - clarified that 'mimeMediaType' values can
        include any parameters from the IANA Registry, not just
        charset parameters.
    31. Section 4.1.9.1 - clarified that 'application/octet-stream'
        auto-sensing can happen at create request time and/or
        job/document processing time.
    32. Section 4.1.9.1 - clarified that auto-sensing involves the
        Printer examining some number of octets of document data using
        an implementation-dependent method.
    33. Section 4.1.14 - clarified that the localization of dateTime
        by the client includes the time zone.
    34. Section 4.2 - clarified that xxx-supported have multiple
        keywords and/or names by adding parentheses to the table to
        give:  (1setOf (type3 keyword | name))
    35. Section 4.2.2 - added the 'indefinite' keyword value to the
        "job-hold-until" attribute for use with the create operations
        and Hold-Job and Restart-Job operations.
    36. Section 4.2.6 - added more enum values to the "finishings" Job
        Template attribute.
    37. Section 4.2.6 - clarified that the landscape definition is a
        rotation of the image with respect to the medium.
    38. Section 4.3.7 - added that a forwarding server that cannot get
        any job state MAY return the job's state as 'completed',
        provided that it also return the new 'queued-in-device' job
        state reason.
    39. Section 4.3.7.2 - added the Partitioning of Job States section
        to clarify the concepts of Job Retention, Job History, and Job
        Removal.
    40. Section 4.3.8 - added 'job-data-insufficient' job state reason
        to indicate whether sufficient data has arrived for the
        document to start to be processed.
    41. Section 4.3.8 - added 'document-access-error' job state reason
        to indicate an access error of any kind.
    42. Section 4.3.8 - added 'job-queued-for-marker' job state reason
        to indicate whether the job has completed some processing and
        is waiting for the marker.
    43. Section 4.3.8 - added 'unsupported-compression' and
        'compression-error' job state reasons to indicate compression
        not supported or compression processing error after the create
        has been accepted.

Hastings, et al. Standards Track [Page 218] RFC 2911 IPP/1.1: Model and Semantics September 2000

    44. Section 4.3.8 - added 'unsupported-document-format' and
        'document-format-error' job state reasons to indicate document
        not supported or document format processing error after the
        create has been accepted.
    45. Section 4.3.8 - added 'queued-in-device' job state reason to
        indicate that a job as been forwarded to a print system or
        device that does not provide any job status.
    46. Section 4.3.10 - added "job-detailed-status-messages (1setOf
        text(MAX)) for returning detailed error messages.
    47. Section 4.3.11 - added the "job-document-access-errors (1setOf
        text(MAX))
    48. Section 4.3.14.2 - clarified that the time recorded is the
        first time processing since the create operation or the
        Restart-Job operation.
    49. Section 4.3.14.2 and 4.3.14.3 - clarified that the out-of-band
        value 'no-value' is returned if the job has not started
        processing or has not completed, respectively.
    50. Section 4.3.14 - Added the OPTIONAL "date-time-at-creation",
        "date-time-at-processing", and "date-time-at-completed" Event
        Time Job Description attributes
    51. Section 4.4.3 - added the 'tls' value to "uri-security-
        supported" attribute.
    52. Section 4.4.3 - clarified "uri-security-supported" is
        orthogonal to Client Authentication so that 'none' does not
        exclude Client Authentication.
    53. Section 4.4.11 - simplified the "printer-state" descriptions
        while generalizing to allow high end devices that interpret
        one or more jobs while marking another.  Indicated that
        'spool-area-full' and 'stopped-partly' "printer-state-reasons"
        may be used to provide further state information.
    54. Section 4.4.12 - added the 'moving-to-paused' keyword value to
        the "printer-state-reasons" attribute for use with the Pause-
        Printer operation.
    55. Section 4.4.12 - replaced the duplicate 'marker-supply-low'
        keyword with the missing 'toner-empty' keyword for the
        "printer-state-reasons" attribute.  (This correction was also
        made before RFC 2566 was published).
    56. Section 4.4.12 - clarified 'spool-area-full' "printer-state-
        reasons" to include non-spooling printers to indicate when it
        can and cannot accept another job.
    57. Section 4.4.15 - added the enum values to the "operations-
        supported" attribute for the new operations.  Clarified that
        the values of this attribute are encoded as any enum, namely
        32-bit values.
    58. Section 4.4.30 - clarified that the dateTime value of
        "printer-current-time" is on a "best efforts basis".  If a
        proper date-time cannot be obtained, the implementation
        returns the 'no-value' out-of-band value.  Also clarified that

Hastings, et al. Standards Track [Page 219] RFC 2911 IPP/1.1: Model and Semantics September 2000

        the time zone NEED NOT be the time zone that the people near
        the device use and that the client SHOULD display the dateTime
        attributes in the user's local time.
    59. Sections 4.4.36 and 4.4.37 - added the OPTIONAL "pages-per-
        minute" and "pages-per-minute-color" Printer Description
        attributes.
    60. Section 5.1 - clarified that the client conformance
        requirements apply to clients controlled by an end user and
        clients in servers.
    61. Section 5.1 - clarified that any response MAY contain
        additional attribute groups, attributes, attribute syntaxes,
        or attribute values.
    62. Section 5.1 - clarified that a client SHOULD do its best to
        prevent a channel from being closed by a lower layer when the
        channel is flow controlled off by the IPP Printer.
    63. Section 5.2 - clarified that the IPP object requirements apply
        to objects embedded in devices or that are parts of servers.
    64. Section 5.2.2 - clarified that IPP objects MAY return
        operation responses that contain attribute groups, attribute
        names, attribute syntaxes, attribute values, and status codes
        that are extensions to this standard.
    65. Section 6 - changed the terminology of "private extensions" to
        "vendor extensions" and indicated that they are registered
        with IANA along with IETF standards track extensions.
    66. Section 6.7 - inserted this section on registering out-of-band
        attribute values with IANA as extensions.
    67. Section 8.3 - clarified the use of URIs for each Client
        Authentication mechanism.
    68. Section 8.5 - added the security discussion around the new
        operator/administrator operations.
    69. Section 13.1.4.16 - added client-error-compression-not-
        supported (0x040F)
    70. Section 13.1.4.17 - added client-error-compression-error
        (0x0410)
    71. Section 13.1.4.18 - added client-error-document-format-error
        (0x0411)
    72. Section 13.1.4.19 - added client-error-document-access-error
        (0x0412)
    73. Section 13.1.5.10 - added server-error-multiple-document-
        jobs-not-supported (0x0509)
    74. Section 14 - added 'a-white', 'b-white', 'c-white', 'd-white',
        and 'e-white' and clarified that the existing 'a', 'b', 'c',
        'd', and 'e' values are size values.  Added American,
        Japanese, and European Engineering sizes, filled out
        -transparent and - translucent media names and drawings for
        the synchro cut sizes.

Hastings, et al. Standards Track [Page 220] RFC 2911 IPP/1.1: Model and Semantics September 2000

    75. Section 16 - softened the RECOMMENDATION for IPP Printer
        attributes in a Directory schema so that they can have
        equivalents.
    76. Section 16 - added the OPTIONAL "pages-per-minute" and
        "pages-per-minute-color" Printer attributes to the Directory
        schema.
    77. Section 16 - added OPTIONAL "multiple-document-jobs-supported"
        to the Directory schema.
    78. Section 16 - added RECOMMENDED "uri-authentication-supported",
        "ipp-versions-supported", and "compression-supported" to the
        Directory schema.
 The following changes in semantics and/or conformance have been
 incorporated into this document:
    1.  Section 3.1.6.3 - allowed a Printer to localize the
        "detailed-status-message" operation response attribute, but
        indicated that such localization might obscure the technical
        meaning of such messages.
    2.  Section 3.1.8, 5.2.4, and 13.1.5.4 - Clients and IPP objects
        MUST support version 1.1 conformance requirements.   It is
        recommended that they interoperate with 1.0.  Also clarified
        that IPP Printers MUST accept '1.1' requests.   It is
        recommended that they also accept '1.x' requests.
    3.  Section 3.2.1.1 and section 4.4.32 - changed the "compression"
        operation and the "compression-supported" Printer Description
        attribute from OPTIONAL to REQUIRED.
    4.  Sections 3.2.1.2 and 4.3.8 - changed "job-state-reasons" from
        RECOMMENDED to REQUIRED, so that "job-state-reasons" MUST be
        returned in create operation responses.
    5.  Sections 3.2.4, 3.3.1, 4.4.16, and 16 - changed Create-
        Job/Send-Document so that they MAY be implemented while only
        supporting one document jobs.  Added the "multiple-document-
        jobs-supported" boolean Printer Description attribute to
        indicate whether Create-Job/Send-Document support multiple
        document jobs or not.  Added to the Directory schema.
    6.  Section 4.1.9 - deleted 'text/plain; charset=iso-10646-ucs-2',
        since binary is not legal with the 'text' type.
    7.  Section 4.1.9.1 - added the RECOMMENDATION that a Printer
        indicate by printing on the job's job-start-sheet that auto-
        sensing has occurred and what document format was auto-sensed.
    8.  Section 4.2.4 - indicated that the "multiple-document-
        handling" Job Template attribute MUST be supported with at
        least one value if the Printer supports multiple documents per
        job

Hastings, et al. Standards Track [Page 221] RFC 2911 IPP/1.1: Model and Semantics September 2000

    9.  Section 4.3.7.2 - indicated that the 'job-restartable' job
        state reason SHOULD be supported if the Restart-Job operation
        is supported.
    10. Section 4.3.8 - changed "job-state-reasons" from RECOMMENDED
        to REQUIRED.
    11. Section 4.3.8 - clarified the conformance of the values of the
        "job-state-reasons" attribute by copying conformance
        requirements from other sections of the document so that it is
        clear from reading the definition of "job-state-reasons" which
        values MUST or SHOULD be supported.  The 'none',
        'unsupported-compression', and 'unsupported-document-format'
        values MUST be supported.  The 'job-hold-until-specified'
        SHOULD be specified if the "job-hold-until" Job Template is
        supported.  The following values SHOULD be supported:  'job-
        canceled-by-user', 'aborted-by-system', and 'job-completed-
        successfully'.  The
        'job-canceled-by-operator' SHOULD be supported if the
        implementation permits canceling by other than the job owner.
        The 'job-canceled-at-device' SHOULD be supported if the device
        supports canceling jobs at the console.  The 'job-completed-
        with-warnings' SHOULD be supported, if the implementation
        detects warnings.  The 'job-completed-with-errors' SHOULD be
        supported if the implementation detects errors.  The 'job-
        restartable' SHOULD be supported if the Restart-Job operation
        is supported.
    12. Section 4.3.10 - allowed a Printer to localize the "job-
        detailed-status-message" Job Description attribute, but
        indicated that such localization might obscure the technical
        meaning of such messages.
    13. Section 4.3.14 - changed the "time-at-creation", "time-at-
        processing", and "time-at-completed" Event Time Job
        Description attributes from OPTIONAL to REQUIRED.
    14. Section 4.3.14.4 - added the REQUIRED "job-printer-up-time
        (integer(1:MAX))" Job Description attribute as an alias for
        "printer-up-time" to reduce number of operations to get job
        times.
    15. Section 4.4.2 - added the REQUIRED "uri-authentication-
        supported (1setOf type2 keyword)" Printer Description
        attribute to describe the Client Authentication used by each
        Printer URI.
    16. Section 4.4.12 - changed "printer-state-reasons" Printer
        Description attribute from OPTIONAL to REQUIRED.
    17. Section 4.4.12 - changed 'paused' value of "printer-state-
        reasons" to MUST if Pause-Printer operation is supported.

Hastings, et al. Standards Track [Page 222] RFC 2911 IPP/1.1: Model and Semantics September 2000

    18. Section 4.4.14 - added the REQUIRED "ipp-versions-supported
        (1setOf keyword)" Printer Description attribute, since IPP/1.1
        Printers do not have to support version '1.0' conformance
        requirements.  Section 4.4.16 - added the "multiple-document-
        jobs-supported (boolean)" Printer Description attribute so
        that a client can tell whether a Printer that supports
        Create-Job/Send-Document supports multiple document jobs or
        not.  This attribute is REQUIRED if the Create-Job operation
        is supported.
    19. Section 4.4.24 - changed the "queued-job-count" Printer
        Description attribute from RECOMMENDED to REQUIRED.
    20. Section 4.4.32 - changed "compression-supported (1setOf type3
        keyword)" Printer Description attribute from OPTIONAL to
        REQUIRED.
    21. Section 5.1 - changed the client security requirements from
        RECOMMENDED non-standards track SSL3 to MUST support Client
        Authentication as defined in the IPP/1.1 Encoding and
        Transport document [RFC2910].  A client SHOULD support
        Operation Privacy and Server Authentication as defined in the
        IPP/1.1 Encoding and Transport document [RFC2910].
    22. Section 5.2.7 - changed the IPP object security requirements
        from OPTIONAL non-standards track SSL3 to SHOULD contain
        support for Client Authentication as defined in the IPP/1.1
        Encoding and Transport document [RFC2910].  A Printer
        implementation MAY allow an administrator to configure the
        Printer so that all, some, or none of the users are
        authenticated.  An IPP Printer implementation SHOULD contain
        support for Operation Privacy and Server Authentication as
        defined in the IPP/1.1 Encoding and Transport document
        [RFC2910].  A Printer implementation MAY allow an
        administrator to configure the degree of support for Operation
        Privacy and Server Authentication.  Security MUST NOT be
        compromised when the client supplies a lower version-number in
        a request.
    23. Section 14 (Appendix C): Corrected typo, changing the keyword
        'iso-10-white' to 'iso-a10-white'.
 See also the "IPP/1.1 Encoding and Transport" [RFC2910] document for
 differences between IPP/1.0 [RFC2565] and IPP/1.1 [RFC2910].

Hastings, et al. Standards Track [Page 223] RFC 2911 IPP/1.1: Model and Semantics September 2000

18. Full Copyright Statement

 Copyright (C) The Internet Society (2000).  All Rights Reserved.
 This document and translations of it may be copied and furnished to
 others, and derivative works that comment on or otherwise explain it
 or assist in its implementation may be prepared, copied, published
 and distributed, in whole or in part, without restriction of any
 kind, provided that the above copyright notice and this paragraph are
 included on all such copies and derivative works.  However, this
 document itself may not be modified in any way, such as by removing
 the copyright notice or references to the Internet Society or other
 Internet organizations, except as needed for the purpose of
 developing Internet standards in which case the procedures for
 copyrights defined in the Internet Standards process must be
 followed, or as required to translate it into languages other than
 English.
 The limited permissions granted above are perpetual and will not be
 revoked by the Internet Society or its successors or assigns.
 This document and the information contained herein is provided on an
 "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
 TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
 BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
 HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
 MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

Acknowledgement

 Funding for the RFC Editor function is currently provided by the
 Internet Society.

Hastings, et al. Standards Track [Page 224]

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