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rfc:rfc2421

Network Working Group G. Vaudreuil Request for Comments: 2421 Lucent Technologies Obsoletes: 1911 G. Parsons Category: Standards Track Northern Telecom

                                                        September 1998
            Voice Profile for Internet Mail - version 2

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 (1998).  All Rights Reserved.

Overview

 This document profiles Internet mail for voice messaging.  It
 obsoletes RFC 1911 which describes version 1 of the profile.  A list
 of changes from that document are noted in Appendix F.  As well,
 Appendix A summarizes the protocol profiles of this version of VPIM.
 Please send comments on this document to the EMA VPIM Work Group
 mailing list:  <vpim-l@ema.org>

Working Group Summary

 This profile is not the product of an IETF working group, though
 several have reviewed the document.  It is instead the product of the
 VPIM Work Group of the Electronic Messaging Association (EMA).  This
 work group, which has representatives from most major voice mail
 vendors and several email vendors, has held several interoperability
 demonstrations between voice messaging vendors and is currently
 promoting VPIM trials and deployment.

Vaudreuil & Parsons Standards Track [Page 1] RFC 2421 VPIM v2 September 1998

Table of Contents

 1. ABSTRACT .........................................................3
 2. SCOPE ............................................................3
   2.1 Voice Messaging System Limitations ............................3
   2.2 Design Goals ..................................................4
 3. PROTOCOL RESTRICTIONS ............................................5
 4. VOICE MESSAGE INTERCHANGE FORMAT .................................6
   4.1 Message Addressing Formats ....................................6
   4.2 Message Header Fields .........................................9
   4.3 Voice Message Content Types ..................................15
   4.4 Other Message Content Types ..................................21
   4.5 Forwarded Messages ...........................................23
   4.6 Reply Messages ...............................................23
   4.7 Notification Messages ........................................24
 5. MESSAGE TRANSPORT PROTOCOL ......................................24
   5.1 ESMTP Commands ...............................................25
   5.2 ESMTP Keywords ...............................................27
   5.3 ESMTP Parameters - MAIL FROM .................................28
   5.4 ESMTP Parameters - RCPT TO ...................................29
   5.5 ESMTP - SMTP Downgrading .....................................29
 6. DIRECTORY ADDRESS RESOLUTION ....................................30
 7. IMAP ............................................................30
 8. MANAGEMENT PROTOCOLS ............................................30
   8.1 Network Management ...........................................31
 9. CONFORMANCE REQUIREMENTS ........................................31
 10. SECURITY CONSIDERATIONS ........................................32
   10.1 General Directive ...........................................32
   10.2 Threats and Problems ........................................32
   10.3 Security Techniques .........................................33
 11. REFERENCES .....................................................33
 12. ACKNOWLEDGMENTS ................................................36
 13. AUTHORS' ADDRESSES .............................................36
 14. APPENDIX A - VPIM REQUIREMENTS SUMMARY .........................37
 15. APPENDIX B - EXAMPLE VOICE MESSAGES ............................45
 16. APPENDIX C - EXAMPLE ERROR VOICE PROCESSING ERROR CODES ........50
 17. APPENDIX D - EXAMPLE VOICE PROCESSING DISPOSITION TYPES ........51
 18. APPENDIX E - IANA REGISTRATIONS ................................52
   18.1 vCard EMAIL Type Definition for VPIM ........................52
   18.2 Voice Content-Disposition Parameter Definition ..............52
 19. APPENDIX F - CHANGE HISTORY: RFC 1911 TO THIS DOCUMENT .........54
 20. FULL COPYRIGHT NOTICE ..........................................56

Vaudreuil & Parsons Standards Track [Page 2] RFC 2421 VPIM v2 September 1998

1. Abstract

 A class of special-purpose computers has evolved to provide voice
 messaging services.  These machines generally interface to a
 telephone switch and provide call answering and voice messaging
 services.  Traditionally, messages sent to a non-local machine are
 transported using analog networking protocols based on DTMF signaling
 and analog voice playback.  As the demand for networking increases,
 there is a need for a standard high-quality digital protocol to
 connect these machines.  The following document is a profile of the
 Internet standard MIME and ESMTP protocols for use as a digital voice
 messaging networking protocol. The profile is referred to as VPIM
 (Voice Profile for Internet Mail) in this document.
 This profile is based on earlier work in the Audio Message
 Interchange Specification (AMIS) group that defined a voice messaging
 protocol based on X.400 technology.  This profile is intended to
 satisfy the user requirements statement from that earlier work with
 the industry standard ESMTP/MIME mail protocol infrastructures
 already used within corporate intranets. This second version of VPIM
 is based on implementation experience and obsoletes RFC 1911 which
 describes version 1 of the profile.

2. Scope

 MIME is the Internet multipurpose, multimedia messaging standard.
 This document explicitly recognizes its capabilities and provides a
 mechanism for the exchange of various messaging technologies,
 primarily voice and facsimile.
 This document specifies a restricted profile of the Internet
 multimedia messaging protocols for use between voice processing
 server platforms.  These platforms have historically been special-
 purpose computers and often do not have the same facilities normally
 associated with a traditional Internet Email-capable computer.  As a
 result, VPIM also specifies additional functionality as it is needed.
 This profile is intended to specify the minimum common set of
 features to allow interworking between compliant systems.

2.1 Voice Messaging System Limitations

 The following are typical limitations of voice messaging platform
 which were considered in creating this baseline profile.
   1) Text messages are not normally received and often cannot be
   easily displayed or viewed.  They can often be processed only via
   text-to-speech or text-to-fax features not currently present in
   many of these machines.

Vaudreuil & Parsons Standards Track [Page 3] RFC 2421 VPIM v2 September 1998

   2) Voice mail machines usually act as an integrated Message
   Transfer Agent, Message Store and User Agent.  There is no relaying
   of messages, and RFC 822 header fields may have limited use in the
   context of the limited messaging features currently deployed.
   3) Voice mail message stores are generally not capable of
   preserving the full semantics of an Internet message.  As such, use
   of a voice mail machine for gatewaying is not supported.  In
   particular, storage of recipient lists, "Received" lines, and
   "Message-ID" may be limited.
   4) Internet-style distribution/exploder mailing lists are not
   typically supported.  Voice mail machines often implement only
   local alias lists, with error-to-sender and reply-to-sender
   behavior.  Reply-all capabilities using a CC list are not generally
   available.
   5) Error reports must be machine-parsable so that helpful responses
   can be voiced to users whose only access mechanism is a telephone.
   6) The voice mail systems generally limit address entry to 16 or
   fewer numeric characters, and normally do not support alphanumeric
   mailbox names.  Alpha characters are not generally used for mailbox
   identification as they cannot be easily entered from a telephone
   terminal.

2.2 Design Goals

 It is a goal of this profile to make as few restrictions and
 additions to the existing Internet mail protocols as possible while
 satisfying the requirements for interoperability with current
 generation voice messaging systems.  This goal is motivated by the
 desire to increase the accessibility to digital messaging by enabling
 the use of proven existing networking software for rapid development.
 This specification is intended for use on a TCP/IP network; however,
 it is possible to use the SMTP protocol suite over other transport
 protocols.  The necessary protocol parameters for such use is outside
 the scope of this document.
 This profile is intended to be robust enough to be used in an
 environment, such as the global Internet with installed-base gateways
 which do not understand MIME, though typical use is expected to be
 within corporate intranets.  Full functionality, such as reliable
 error messages and binary transport, will require careful selection
 of gateways (e.g., via MX records) to be used as VPIM forwarding
 agents.  Nothing in this document precludes use of general purpose
 MIME email packages to read and compose VPIM messages.  While no

Vaudreuil & Parsons Standards Track [Page 4] RFC 2421 VPIM v2 September 1998

 special configuration is required to receive VPIM compliant messages,
 some may be required to originate compliant structures.
 It is expected that a VPIM messaging system will be managed by a
 system administrator who can perform TCP/IP network configuration.
 When using facsimile or multiple voice encodings, it is suggested
 that the system administrator maintain a list of the capabilities of
 the networked mail machines to reduce the sending of undeliverable
 messages due to lack of feature support.  Configuration,
 implementation and management of these directory listing capabilities
 are local matters.

3. Protocol Restrictions

 This protocol does not limit the number of recipients per message.
 Where possible, server implementations should not restrict the number
 of recipients in a single message.  It is recognized that no
 implementation supports unlimited recipients, and that the number of
 supported recipients may be quite low.
 This protocol does not limit the maximum message length.
 Implementers should understand that some machines will be unable to
 accept excessively long messages.  A mechanism is defined in the RFC
 1425 SMTP service extensions to declare the maximum message size
 supported.
 The message size indicated in the ESMTP SIZE parameter is in bytes,
 not minutes or seconds.  The number of bytes varies by voice encoding
 format and includes the MIME wrapper overhead.  If the length must be
 known before sending, an approximate translation into minutes or
 seconds can be performed if the voice encoding is known.
 The following sections describe the restrictions and additions to
 Internet mail protocols that are required to be compliant with this
 VPIM v2 profile. Though various SMTP, ESMTP and MIME features are
 described here, the implementer is referred to the relevant RFCs for
 complete details. It is also advisable to check for IETF drafts of
 various Internet Mail specifications that are later than the most
 recent RFCs since, for example, MIME has yet to be published as a
 full IETF Standard. The table in Appendix A summarizes the protocol
 details of this profile.
 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
 "SHOULD", "SHOULD NOT", "RECOMMENDED",  "MAY", and "OPTIONAL" in this
 document are to be interpreted as described in [REQ].

Vaudreuil & Parsons Standards Track [Page 5] RFC 2421 VPIM v2 September 1998

4. Voice Message Interchange Format

 The voice message interchange format is a profile of the Internet
 Mail Protocol Suite.  Any Internet Mail message containing the format
 defined in this section is referred to as a VPIM Message in this
 document.  As a result, this document assumes an understanding of the
 Internet Mail specifications.  Specifically, VPIM references
 components from the message format standard for Internet messages
 [RFC822], the Multipurpose Internet Message Extensions [MIME], the
 X.400 gateway specification [X.400], delivery status and message
 disposition notifications [REPORT][DSN][DRPT][STATUS][MDN], and the
 electronic business card [MIMEDIR][VCARD].

4.1 Message Addressing Formats

 RFC 822 addresses are based on the domain name system.  This naming
 system has two components: the local part, used for username or
 mailbox identification; and the host part, used for global machine
 identification.

4.1.1 VPIM Addresses

 The local part of the address shall be a US-ASCII string uniquely
 identifying a mailbox on a destination system.  For voice messaging,
 the local part is a printable string containing the mailbox ID of the
 originator or recipient.  While alpha characters and long mailbox
 identifiers are permitted, most voice mail networks rely on numeric
 mailbox identifiers to retain compatibility with the limited 10 digit
 telephone keypad.  As a result, some voice messaging systems may only
 be able to handle a numeric local part.  The reception of
 alphanumeric local parts on these systems may result in the address
 being mapped to some locally unique (but confusing to the recipient)
 number or, in the worst case the address could be deleted making the
 message un-replyable.  Additionally, it may be difficult to create
 messages on these systems with an alphanumeric local part without
 complex key sequences or some form of directory lookup (see 6).
 The use of the domain naming system should be transparent to the
 user.  It is the responsibility of the voice mail machine to lookup
 the fully-qualified domain name (FQDN) based on the address entered
 by the user (see 6).
 In the absence of a global directory, specification of the local part
 is expected to conform to international or private telephone
 numbering plans.  It is likely that private numbering plans will
 prevail and these are left for local definition.  However, it is
 RECOMMENDED that public telephone numbers be noted according to the
 international numbering plan described in [E.164]. The indication

Vaudreuil & Parsons Standards Track [Page 6] RFC 2421 VPIM v2 September 1998

 that the local part is a public telephone number is given by a
 preceding `+' (the `+' would not be entered from a telephone keypad,
 it is added by the system as a flag).  Since the primary information
 in the numeric scheme is contained by the digits, other character
 separators (e.g.  `-') may be ignored (i.e. to allow parsing of the
 numeric local mailbox) or may be used to recognize distinct portions
 of the telephone number (e.g. country code).  The specification of
 the local part of a VPIM address can be split into the four groups
 described below:
   1) mailbox number
      - for use as a private numbering plan (any number of digits)
      - e.g.  2722@lucent.com
   2) mailbox number+extension
      - for use as a private numbering plan with extensions
        any number of digits, use of `+' as separator
      - e.g.  2722+111@Lucent.com
   3) +international number
      - for international telephone numbers conforming to E.164
        maximum of 15 digits
      - e.g.  +16137637582@vm.nortel.ca
   4) - for international telephone numbers conforming to E.164
        maximum of 15 digits, with an extension (e.g. behind a
        PBX) that has a maximum of 15 digits.
      - e.g.  +17035245550+230@ema.org
 Note that this address format is designed to be compatible with
 current usage within the voice messaging industry.  It is not
 compatible with the addressing formats of RFCs 2303-2304.  It is
 expected that as telephony services become more widespread on the
 Internet, these addressing formats will converge.

4.1.2 Special Addresses

 Special addresses are provided for compatibility with the conventions
 of Internet mail.  These addresses do not use numeric local
 addresses, both to conform to current Internet practice and to avoid
 conflict with existing numeric addressing plans. Two special
 addresses are RESERVED for use as follows:
 postmaster@domain
 By convention, a special mailbox named "postmaster" MUST exist on all
 systems.  This address is used for diagnostics and should be checked
 regularly by the system manager. This mailbox is particularly likely

Vaudreuil & Parsons Standards Track [Page 7] RFC 2421 VPIM v2 September 1998

 to receive text messages, which is not normal on a voice processing
 platform.  The specific handling of these messages is an individual
 implementation choice.
 non-mail-user@domain
 If a reply to a message is not possible, such as a telephone
 answering message, then the special address "non-mail-user" must be
 used as the originator's address.  Any text name such as "Telephone
 Answering", or the telephone number if it is available, is permitted.
 This special address is used as a token to indicate an unreachable
 originator. For compatibility with the installed base of mail user
 agents, implementations that generate this special address MUST send
 a negative delivery status notification (DSN) for reply messages sent
 to the undeliverable address.  The status code for such NDN's is
 5.1.1 "Mailbox does not exist".
 Example:
     From: Telephone Answering <non-mail-user@mycompany.com>

4.1.3 Distribution Lists

 There are many ways to handle distribution list (DL) expansions and
 none are 'standard'.  Simple alias is a behavior closest to what most
 voice mail systems do today and what is to be used with VPIM
 messages.  That is:
   Reply to the originator - (Address in the RFC822 Reply-to or From
                              field)
   Errors to the submitter - (Address in the MAIL FROM: field of the
                              ESMTP exchange and the Return-Path:
                              RFC 822 field)
 Some proprietary voice messaging protocols include only the recipient
 of the particular copy in the envelope and include no "header fields"
 except date and per-message features.  Most voice messaging systems
 do not provide for "Header Information" in their messaging queues and
 only include delivery information.  As a result, recipient
 information MAY be in either the To or CC header fields. If all
 recipients cannot be presented (e.g. unknown DL expansion) then the
 recipient header fields MUST be omitted to indicate that an accurate
 list of recipients (e.g. for use with a reply-all capability) is not
 known.

Vaudreuil & Parsons Standards Track [Page 8] RFC 2421 VPIM v2 September 1998

4.2 Message Header Fields

 Internet messages contain a header information block.  This header
 block contains information required to identify the sender, the list
 of recipients, the message send time, and other information intended
 for user presentation.  Except for specialized gateway and mailing
 list cases, header fields do not indicate delivery options for the
 transport of messages.
 Distribution list processors are noted for modifying or adding to the
 header fields of messages that pass through them.  VPIM systems MUST
 be able to accept and ignore header fields that are not defined here.
 The following header lines are permitted for use with VPIM voice
 messages:

4.2.1 From

 The originator's fully-qualified domain address (a mailbox address
 followed by the fully-qualified domain name).  The user listed in
 this field should be presented in the voice message envelope as the
 originator of the message.
 Systems compliant with this profile SHOULD provide the text personal
 name of the voice message originator in a quoted phrase, if the name
 is available.  Text names of corporate or positional mailboxes MAY be
 provided as a simple string. From [RFC822]
 Example:
     From: "Joe S. User" <12145551212@mycompany.com>
     From: Technical Support <611@serviceprovider.com>
 The From address SHOULD be used for replies (see 4.6).  However, if
 the From address contains <non-mail-user@domain>, the user SHOULD NOT
 be offered the option to reply, nor should notifications be sent to
 this address.
 Voice mail machines may not be able to support separate attributes
 for the FROM, REPLY-TO, and SENDER header field and the SMTP MAIL
 FROM command, VPIM conforming systems SHOULD set these values to the
 same address.  Use of addresses different than those present in the
 From header field address may result in unanticipated behavior.

Vaudreuil & Parsons Standards Track [Page 9] RFC 2421 VPIM v2 September 1998

4.2.2 To

 The To header contains the recipient's fully-qualified domain
 address.  There may be one or more To: fields in any message.
 Example:
     To: +12145551213@mycompany.com
 Systems compliant to this profile SHOULD provide a list of recipients
 only if all recipients are provided.  The To header MUST NOT be
 included in the message if the sending message transport agent (MTA)
 cannot resolve all the addresses in it, e.g. if an address is a DL
 alias for which the expansion is unknown (see 4.1.3).  If present,
 the addresses in the To header MAY be used for a reply message to all
 recipients.
 Systems compliant to this profile MAY also discard the To addresses
 of incoming messages because of the inability to store the
 information.  This would, of course, make a reply-to-all capability
 impossible.

4.2.3 Cc

 The cc header contains additional recipients' fully-qualified domain
 addresses. Many voice mail systems maintain only sufficient envelope
 information for message delivery and are not capable of storing or
 providing a complete list of recipients.
 Systems compliant to this profile SHOULD provide a list of recipients
 only if all disclosed recipients can be provided.  The list of
 disclosed recipients does not include those sent via a blind copy. If
 not, systems SHOULD omit the To and Cc header fields to indicate that
 the full list of recipients is unknown.
 Example:
     Cc: +12145551213@mycompany.com
 Systems compliant to this profile MAY discard the Cc addresses of
 incoming messages as necessary.    If a list of Cc or to addresses is
 present, these addresses MAY be used for a reply message to all
 recipients.

Vaudreuil & Parsons Standards Track [Page 10] RFC 2421 VPIM v2 September 1998

4.2.4 Date

 The Date header contains the date, time, and time zone in which the
 message was sent by the originator.  The time zone SHOULD be
 represented in a four-digit time zone offset, such as -0500 for North
 American Eastern Standard Time.  This may be supplemented by a time
 zone name in parentheses, e.g., "-0900 (PDT)".  Compliant
 implementations SHOULD be able to convert RFC 822 date and time
 stamps into local time.
 Example:
     Date: Wed, 28 Jul 96 10:08:49 -0800 (PST)
 The sending system MUST report the time the message was sent. If the
 VPIM sender is relaying a message from a system which does not
 provide a time stamp, the time of arrival at the VPIM system SHOULD
 be used as the date.  From [RFC822]

4.2.5 Sender

 The Sender header field contains the actual address of the originator
 if the message is sent by an agent on behalf of the author indicated
 in the From: field. This header field MAY be sent by VPIM conforming
 system.  If it is present in a VPIM message, the receiving VPIM
 implementation may ignore the field and only present the From header
 field.

4.2.6 Return Path

 The Return-path header is added by the final delivering SMTP server.
 If present, it contains the address from the MAIL FROM parameter of
 the ESMTP exchange (see 5.1.2). Any error messages resulting from the
 delivery failure MUST be sent to this address (see [DRPT] for
 additional details).  Note that if the Return-path is null ("<>"),
 e.g. no path, loop prevention or confidential, a notification MUST
 NOT be sent.  If the Return path address is not available (either
 from this header or the MAIL FROM parameter) the From address may be
 used to deliver notifications.

4.2.7 Message-id

 The Message-id header contains a unique per-message identifier.  A
 unique message-id MUST be generated for each message sent from a
 compliant implementation.
 The message-id is not required to be stored on the receiving system.
 This identifier MAY be used for tracking, auditing, and returning

Vaudreuil & Parsons Standards Track [Page 11] RFC 2421 VPIM v2 September 1998

 receipt notification reports.  From [RFC822]
 Example:
     Message-id: <12345678@mycompany.com>

4.2.8 Reply-To

 If present, the reply-to header provides a preferred address to which
 reply messages should be sent (see 4.6).  Typically, voice mail
 systems can only support one originator of a message so it is
 unlikely that this field can be supported.  A compliant system SHOULD
 NOT send a Reply-To header. However, if a reply-to header is present,
 a reply-to sender message MAY be sent to the address specified (that
 is, overwriting From). From [RFC822] This preferred address of the
 originator must also be provided in the originator's vCard EMAIL
 attribute, if present (see 4.3.3).

4.2.9 Received

 The Received header contains trace information added to the beginning
 of a RFC 822 message by MTAs.  This is the only header permitted to
 be added by an MTA.  Information in this header is useful for
 debugging when using an US-ASCII message reader or a header parsing
 tool.
 A compliant system MUST add Received header fields when acting as a
 gateway and MUST NOT remove any Received fields when relaying
 messages to other  MTAs or gateways..  These header fields MAY be
 ignored or deleted when the message is received at the final
 destination. From [RFC822]

4.2.10 MIME Version

 The MIME-Version header indicates that the message conforms to the
 MIME message format specification. Systems compliant with this
 specification SHOULD include a comment with the words "(Voice 2.0)".
 RFC 1911 defines an earlier version of this profile and uses the
 token (Voice 1.0). From [MIME1][VPIM1]
 Example:
     MIME-Version: 1.0 (Voice 2.0)
 This identifier is intended for information only and SHOULD NOT be
 used to semantically identify the message as being a VPIM message.
 Instead, the presence of the content defined in [V-MSG] SHOULD be
 used if identification is necessary.

Vaudreuil & Parsons Standards Track [Page 12] RFC 2421 VPIM v2 September 1998

4.2.11 Content-Type

 The content-type header declares the type of content enclosed in the
 message. The typical top level content in a VPIM Message SHOULD be
 multipart/voice-message, a mechanism for bundling several components
 into a single identifiable voice message.  The allowable contents are
 detailed in section 4.3 of this document.  From [MIME2]

4.2.12 Content-Transfer-Encoding

 Because Internet mail was initially specified to carry only 7-bit
 US-ASCII text, it may be necessary to encode voice and fax data into
 a representation suitable for that environment.  The content-
 transfer-encoding header describes this transformation if it is
 needed.  Compliant implementations MUST recognize and decode the
 standard encodings, "Binary", "7bit, "8bit", "Base64" and "Quoted-
 Printable".  The allowable content-transfer-encodings are specified
 in section 4.3.  From [MIME1]

4.2.13 Sensitivity

 The sensitivity header, if present, indicates the requested privacy
 level.  The case-insensitive values "Personal" and "Private" are
 specified. If no privacy is requested, this field is omitted.
 If a sensitivity header is present in the message, a compliant system
 MUST prohibit the recipient from forwarding this message to any other
 user.  A compliant system, however, SHOULD allow the responder to
 reply to a sensitive message, but SHOULD NOT include the original
 message content.  The sensitivity of the reply message MAY be set by
 the responder.
 If the receiving system does not support privacy and the sensitivity
 is one of "Personal" or "Private", a negative delivery status
 notification must sent to the originator with the appropriate status
 code indicating that privacy could not be assured. The message
 contents SHOULD  be returned to the sender to allow for a voice
 context with the notification. A non-delivery notification to a
 private message SHOULD NOT be tagged private since it will be sent to
 the originator.  From: [X.400]

4.2.14 Importance

 Indicates the requested importance to be given by the receiving
 system.  The case-insensitive values "low", "normal" and "high" are
 specified.  If no special importance is requested, this header may be
 omitted and the value assumed to be "normal".

Vaudreuil & Parsons Standards Track [Page 13] RFC 2421 VPIM v2 September 1998

 Compliant implementations MAY use this header to indicate the
 importance of a message and may order messages in a recipient's
 mailbox. From: [X.400]

4.2.15 Subject

 The subject field is often provided by email systems but is not
 widely supported on Voice Mail platforms. For compatibility with text
 based mailbox interfaces, a text subject field SHOULD be generated by
 a compliant implementation but MAY be discarded if present by a
 receiving system.  From [RFC822]
 It is recommended that voice messaging systems that do not support
 any text user interfaces (e.g. access only by a telephone) insert a
 generic subject header of "VPIM Message" for the benefit of text
 enabled recipients.

4.2.16 Disposition-Notification-To

 This header MAY be present to indicate that the sender is requesting
 a receipt notification from the receiving user agent.  This message
 disposition notification (MDN) is typically sent by the user agent
 after the user has listened to the message and consented to an MDN
 being sent
 Example:
     Disposition-notification-to: +12145551213@mycompany.com
 The presence of a Disposition-notification-to header in a message is
 merely a request for an MDN described in 4.4.5.  The recipients' user
 agents are always free to silently ignore such a request so this
 header does not burden any system that does not support it.  From
 [MDN].

4.2.17 Disposition-Notification-Options

 This header MAY be present to define future extensions parameters for
 an MDN requested by the presence of the header in the previous
 section.  Currently no parameters are defined by this document or by
 [MDN].  However, this header MUST be parsed if present, if MDNs are
 supported.  If it contains a extension parameter that is required for
 proper MDN generation (noted with "=required"), then an MDN MUST NOT
 be sent if the parameter is not understood.  See [MDN] for complete
 details.

Vaudreuil & Parsons Standards Track [Page 14] RFC 2421 VPIM v2 September 1998

 Example:
     Disposition-notification-options:
        whizzbang=required,foo

4.3 Voice Message Content Types

 MIME, introduced in [MIME1], is a general-purpose message body format
 that is extensible to carry a wide range of body parts.  It provides
 for encoding binary data so that it can be transported over the 7-bit
 text-oriented SMTP protocol.  This transport encoding (denoted by the
 Content-Transfer-Encoding header field) is in addition to the audio
 encoding required to generate a binary object.
 MIME defines two transport encoding mechanisms to transform binary
 data into a 7 bit representation, one designed for text-like data
 ("Quoted-Printable"), and one for arbitrary binary data ("Base64").
 While Base64 is dramatically more efficient for audio data, either
 will work.  Where binary transport is available, no transport
 encoding is needed, and the data can be labeled as "Binary".
 An implementation in compliance with this profile SHOULD send audio
 and/or facsimile data in binary form when binary message transport is
 available.  When binary transport is not available, implementations
 MUST encode the audio and/or facsimile data as Base64.  The detection
 and decoding of "Quoted-Printable", "7bit", and "8bit" MUST be
 supported in order to meet MIME requirements and to preserve
 interoperability with the fullest range of possible devices.
 However, if a content is received in a transfer encoding that cannot
 be rendered to the user, an appropriate negative delivery status
 notification MUST be sent.
 The content types described in this section are identified for use
 within the multipart/voice-message content.  This content, which is
 the fundamental part of a VPIM message, is referred to as a VPIM
 voice message in this document.
 Only the contents profiled subsequently can be sent within a VPIM
 voice message construct (i.e., the mulitpart/voice-message content
 type) to form a simple or a more complex structure (several examples
 are given in Appendix B).  The presence of other contents within a
 VPIM voice message is an error condition and SHOULD result in a
 negative delivery status notification.  When multiple contents are
 present within the multipart/voice-message, they SHOULD be presented
 to the user in the order that they appear in the message.

Vaudreuil & Parsons Standards Track [Page 15] RFC 2421 VPIM v2 September 1998

4.3.1 Multipart/Voice-Message

 This MIME multipart structure provides a mechanism for packaging a
 voice message into one container that is tagged as VPIM v2 compliant.
 The semantic of multipart/Voice-Message (defined in [V-MSG]) is
 identical to multipart/mixed and may be interpreted as that by
 systems that do not recognize this content-type.
 The Multipart/Voice-Message content-type MUST only contain the
 profiled media and content types specified in this section (i.e.
 audio/*, image/*, message/rfc822 and text/directory).  The most
 common will be: spoken name, spoken subject, the message itself,
 attached fax and directory info.  Forwarded messages are created by
 simply using the message/rfc822 construct.
 Conformant implementations MUST send the multipart/voice-message in a
 VPIM message.  In most cases, this Multipart/Voice-Message content
 will be the top level (i.e. in the Content-Type header).  Conformant
 implementations MUST recognize the Multipart/Voice-Message content
 (whether it is a top level content or below a multipart/mixed) and be
 able to separate the contents (e.g. spoken name or spoken subject).

4.3.2 Message/RFC822

 MIME requires support of the Message/RFC822 message encapsulation
 body part.  This body part is used within a multipart/voice-message
 to forward complete messages (see 4.5) or to reply with original
 content (see 4.6). From [MIME2]

4.3.3 Text/Directory

 This content allows for the inclusion of a Versit vCard [VCARD]
 electronic business card within a VPIM message.  The format is
 suitable as an interchange format between applications or systems,
 and is defined independent of the method used to transport it.  It
 provides a useful mechanism to transport information about the
 originator that can be used by the receiving VPIM system (see 6) or
 other local applications
 Each vCard MUST be contained within a Text/Directory content type
 [MIMEDIR] within a VPIM message.  [MIMEDIR] requires that the
 character set MUST be defined as a parameter value (typically us-
 ascii for VPIM) and that the profile SHOULD be defined (the value
 MUST be vCard within VPIM messages).
 Each VPIM message SHOULD be created with a Text/Directory (vCard
 profile) content type that MUST contain the preferred email address,
 telephone number, and text name of the message originator as well as

Vaudreuil & Parsons Standards Track [Page 16] RFC 2421 VPIM v2 September 1998

 the vCard version.  The vCard SHOULD contain the spoken name and role
 of the originator, as well as the revision date.  Any other vCard
 attribute MAY also be present.  The intent is that the vCard be used
 as the source of information to contact the originator (e.g., reply,
 call).If the text/directory content-type is included in a VPIM
 message, the vCard profile [VCARD] MUST be used and MUST specify at
 least the following attributes:
   TEL  -    Public switched telephone number in international (E.164)
             format (various types, typically VOICE)
   EMAIL -   email address (various types, typically INTERNET; the
             type VPIM is optionally used to denote an address that
             supports VPIM messages(see 18.1))
   VERSION - Indicates the version of the vCard profile.  Version 3.0
             [VCARD] MUST be used.
 The following attributes SHOULD be specified:
   N   -   Family Name, Given Name, Additional Names, Honorific
           Prefixes, and Suffixes. Because it is expected that
           recipients using a telephone user interface will use the
           information in the vCard to identify the originator, and
           the GUI will see the information presented in the FROM
           line, all present components in the text name of the FROM
           header field MUST match the values provided by the Vcard.
   ROLE -  The role of the person identified in `N' or `FN', but may
           also be used to distinguish when the sender is a corporate
           or positional mailbox
   SOUND - spoken name sound data (various types, typically 32KADPCM)
   REV  -  Revision of vCard in ISO 8601 date format
 The vCard MAY use other attributes as defined in [VCARD] or
 extensions attributes not yet defined (e.g. capabilities).
 If present, the spoken name attribute MUST be denoted by a content ID
 pointing to an audio/* content elsewhere in the VPIM message.
 A typical VPIM message (i.e. no forwarded parts), MUST only contain
 one vCard -- more than one is an error condition.  A VPIM message
 that contains forwarded messages, though, may contain multiple
 vCards.  However, these vCards MUST be associated with the
 originator(s) of the forwarded message(s) and the originator of the
 forwarding message.  As a result, all forwarded vCards will be

Vaudreuil & Parsons Standards Track [Page 17] RFC 2421 VPIM v2 September 1998

 contained in message/rfc822 contents -- only the vCard of forwarding
 originator will be at the top-level.
 Example:
   Content-Type: text/directory; charset=us-ascii; profile=vCard
   Content-Transfer-Encoding: 7bit
   BEGIN:VCARD
   N:Parsons;Glenn
   ORG:Northern Telecom
   TEL;TYPE=VOICE;MSG;WORK:+1-613-763-7582
   EMAIL;TYPE=INTERNET;glenn.parsons@nortel.ca
   EMAIL;TYPE=INTERNET;VPIM:6137637582@vm.nortel.ca
   SOUND;TYPE=32KADPCM;ENCODING=URI: CID:<part1@VM2-4321>
   REV:19960831T103310Z
   VERSION: 3.0
   END:VCARD

4.3.4 Audio/32KADPCM

 An implementation compliant to this profile MUST send Audio/32KADPCM
 by default for voice [ADPCM].  Receivers MUST be able to accept and
 decode Audio/32KADPCM.  Typically this body contains several minutes
 of message content, however if used for spoken name or subject the
 content should be considerably shorter (i.e. about 10 and 20 seconds
 respectively).
 If an implementation can only handle one voice body, then multiple
 voice bodies (if present) SHOULD be concatenated, and SHOULD NOT be
 discarded.  It is RECOMMENDED that this be done in the same order as
 they were sent. Note that if an Originator Spoken Name audio body and
 a vCard are both present in a VPIM message, the vCard SOUND attribute
 MUST point to this audio body (see 4.3.3).
 While any valid MIME body header MAY be used, several header fields
 have the following semantics when included with this body part:

4.3.4.1 Content-Description:

 This field MAY be present to facilitate the text identification of
 these body parts in simple email readers.  Any values may be used,
 though it may be useful to use values similar to those for Content-
 Disposition.
 Example:
     Content-Description: Big Telco Voice Message

Vaudreuil & Parsons Standards Track [Page 18] RFC 2421 VPIM v2 September 1998

4.3.4.2 Content-Disposition:

 This field MUST be present to allow the parsable identification of
 these body parts.  This is especially useful if, as is typical, more
 than one Audio/32KADPCM body occurs within a single level (e.g.
 multipart/voice-message).  Since a VPIM voice message is intended to
 be automatically played upon display of the message, in the order in
 which the audio contents occur, the audio contents must always be of
 type inline.  However, it is still useful to include a filename
 value, so this should be present if this information is available.
 From [DISP]
 In order to distinguish between the various types of audio contents
 in a VPIM voice message a new disposition parameter "voice" is
 defined with the parameter values below to be used as appropriate
 (see 18.2):
   Voice-Message - the primary voice message,
   Voice-Message-Notification - a spoken delivery notification
     or spoken disposition notification,
   Originator-Spoken-Name - the spoken name of the originator,
   Recipient-Spoken-Name - the spoken name of the recipient if
     available to the originator and present if there is ONLY one
     recipient,
   Spoken-Subject- the spoken subject of the message, typically
     spoken by the originator
 Note that there SHOULD only be one instance of each of these types of
 audio contents per message level.  Additional instances of a given
 type (i.e., parameter value) may occur within an attached forwarded
 voice message.
 Implementations that do not understand the "voice" parameter (or the
 Content-Disposition header) can safely ignore it, and will present
 the audio bodyparts in order (but will not be able to distinguish
 between them).
 Example:
     Content-Disposition: inline; voice=spoken-subject;
                         filename="msg001.726"

4.3.4.3 Content-Duration:

 This field MAY be present to allow the specification of the length of
 the audio bodypart in seconds.  The use of this field on reception is
 a local implementation issue.  From [DUR]

Vaudreuil & Parsons Standards Track [Page 19] RFC 2421 VPIM v2 September 1998

 Example:
     Content-Duration: 33

4.3.4.4 Content-Language:

 This field MAY be present to allow the specification of the spoken
 language of the audio bodypart.  The encoding is defined in [LANG].
 The use of this field on reception is a local implementation issue.
 Example for UK English:
     Content-Language: en-UK

4.3.5 Image/Tiff

 A common image encoding for facsimile, known as TIFF-F, is a
 derivative of the Tag Image File Format (TIFF) and is described in
 several documents.  For the purposes of VPIM, the F Profile of TIFF
 for Facsimile (TIFF-F) is defined in [TIFF-F] and the image/tiff MIME
 content type is defined in [TIFFREG].  While there are several
 formats of TIFF, only TIFF-F is profiled for use in a VPIM voice
 message.  Further, since the TIFF-F file format is used in a store-
 and-forward mode with VPIM, the image MUST be encoded so that there
 is only one image strip per facsimile page.
 All VPIM implementations that support facsimile SHOULD generate
 TIFF-F compatible facsimile contents in the image/tiff;
 application=faxbw sub-type encoding by default.  An implementation
 MAY send this fax content in VPIM voice messages and MUST be able to
 recognize and display it in received messages.  If a fax message is
 received that cannot be rendered to the user (e.g. the receiving VPIM
 system does not support fax), then the system MUST return the message
 with a negative delivery status notification with a media not
 supported status code.
 While any valid MIME body header MAY be used (e.g., Content-
 Disposition to indicate the filename), none are specified to have
 special semantics for VPIM and MAY be ignored.  Note that the content
 type parameter application=faxbw MUST be included in outbound
 messages.  However, inbound messages with or without this parameter
 MUST be rendered to the user (if the rendering software encounters an
 error in the file format, some form of negative delivery status
 notification MUST be sent to the originator).

Vaudreuil & Parsons Standards Track [Page 20] RFC 2421 VPIM v2 September 1998

4.3.6 Proprietary Voice or Fax Formats

 Proprietary voice or fax encoding formats or other standard formats
 MAY be supported under this profile provided a unique identifier is
 registered with the IANA prior to use (see [MIME4]).  The voice
 encodings should be registered as sub-types of Audio and the fax
 encodings should be registered as sub-types of Image
 Use of any other encoding except audio/32kadpcm or image/tiff;
 application=faxbw reduces interoperability in the absence of explicit
 manual system configuration.  A compliant implementation MAY use any
 other encoding with explicit per-destination configuration.

4.4 Other Message Content Types

 An implementation compliant with this profile MAY send additional
 contents in a VPIM message, but ONLY outside of the multipart/voice-
 message.  The content types described in this section are identified
 for use with this profile. Additional contents not defined in this
 profile MUST NOT be used without prior explicit per-destination
 configuration. If an implementation receives a VPIM message that
 contains content types not specified in this profile, their handling
 is a local implementation issue (e.g. the unknown contents MAY be
 discarded if they cannot be presented to the recipient).  Conversely,
 if an implementation receives a non-VPIM message (i.e., without a
 mulitpart/voice-message content type) with any of the contents
 defined in 4.3 & 4.4, it SHOULD deliver those contents, but the full
 message handling is a local issue (e.g. the unknown contents _or_ the
 entire message MAY be discarded).  Implementations MUST issue
 negative delivery status notifications to the originator when any
 form of non-delivery to the recipient occurs.
 The multipart contents defined below MAY be sent as the top level of
 a VPIM message (with other noted contents below them as required.) As
 well, the multipart/mixed content SHOULD be used as the top level of
 a VPIM message to form a more complex structure (e.g., with
 additional content types).  When multiple contents are present, they
 SHOULD be presented to the user in the order that they appear in the
 message.  Several examples are given in Appendix B.

4.4.1 Multipart/Mixed

 MIME provides the facilities for enclosing several body parts in a
 single message. Multipart/Mixed SHOULD only be used for sending
 complex voice or multimedia messages.  That is, as the top level
 Content-Type when sending one of the following contents (in addition
 to the VPIM voice message) in a VPIM message.  Compliant systems MUST
 accept multipart/mixed body parts.  From [MIME2]

Vaudreuil & Parsons Standards Track [Page 21] RFC 2421 VPIM v2 September 1998

4.4.2 Text/Plain

 MIME requires support of the basic Text/Plain content type.  This
 content type has limited applicability within the voice messaging
 environment.  However, because VPIM is a MIME profile, MIME
 requirements should be met.  Compliant VPIM implementations SHOULD
 NOT send the Text/Plain content-type.  Compliant implementations MUST
 accept Text/Plain messages, however, specific handling is left as an
 implementation decision. From [MIME2]
 There are several mechanisms that can be used to support text (once
 accepted) on voice messaging systems including text-to-speech and
 text-to-fax conversions.  If no rendering of the text is possible
 (i.e., it is not possible for the recipient to determine if the text
 is a critical part of the message), the entire message MUST be
 returned to the sender with a negative delivery status notification
 and a media-unsupported status code.

4.4.3 Multipart/Report

 The Multipart/Report is used for enclosing human-readable and machine
 parsable notification (e.g. Message/delivery-status) body parts and
 any returned message content. The multipart/report content-type is
 used to deliver both delivery status reports indicating transport
 success or failure and message disposition notifications to indicate
 post-delivery events such as receipt notification. Compliant
 implementations MUST use the Multipart/Report construct. Compliant
 implementations MUST recognize and decode the Multipart/Report
 content type and its components in order to present the report to the
 user.  From [REPORT]
 Multipart/Report messages from VPIM implementations SHOULD include
 the human-readable description of the error as a spoken audio/*
 content (this speech SHOULD also be made available to the
 notification recipient).  As well, VPIM implementations MUST be able
 to handle (and MAY generate) Multipart/Report messages that encode
 the human-readable description of the error as text.  Note that per
 [DSN] the human-readable part MUST always be present.

4.4.4 Message/Delivery-status

 This MIME body part is used for sending machine-parsable delivery
 status notifications.  Compliant implementations MUST use the
 Message/delivery-status construct when returning messages or sending
 warnings.  Compliant implementations MUST recognize and decode the
 Message/delivery-status content type and present the reason for
 failure to the sender of the message.  From [DSN]

Vaudreuil & Parsons Standards Track [Page 22] RFC 2421 VPIM v2 September 1998

4.4.5 Message/Disposition-notification

 This MIME body part is used for sending machine-parsable receipt
 notification message disposition notifications.  Conforming
 implementations SHOULD use the Message/Disposition-notification
 construct when sending post-delivery message status notifications.
 These MDNs, however, MUST only be sent in response to the presence of
 the Disposition-notification-to header in 4.2.16.  Conforming
 implementations should recognize and decode the Message/Disposition-
 notification content type and present the notification to the user.
 From [MDN]

4.5 Forwarded Messages

 VPIM version 2 explicitly supports the forwarding of voice and fax
 content with voice or fax annotation.  However, only the two
 constructs described below are acceptable in a VPIM message.  Since
 only the first (i.e. message/rfc822) can be recognized as a forwarded
 message (or even multiple forwarded messages), it is RECOMMENDED that
 this construct be used whenever possible.
 Forwarded VPIM messages SHOULD be sent as a multipart/voice-message
 with the entire original message enclosed in a message/rfc822 content
 type and the annotation as a separate Audio/* or image/* body part.
 If the RFC822 header fields are not available for the forwarded
 content, simulated header fields with available information SHOULD be
 constructed to indicate the original sending timestamp, and the
 original sender as indicated in the "From" line.  However, note that
 at least one of "From", "Subject", or "Date" MUST be present.  As
 well, the message/rfc822 content MUST include at least the "MIME-
 Version", and "Content-Type" header fields. From [MIME2]
 In the event that forwarding information is lost through
 concatenation of the original message and the forwarding annotation,
 such as must be done in a gateway between VPIM and the AMIS voice
 messaging protocol, the entire audio content MAY be sent as a single
 Audio/* segment without including any forwarding semantics.

4.6 Reply Messages

 Replies to VPIM messages (and Internet mail messages) are addressed
 to the address noted in the reply-to header (see 4.2.8) if it is
 present, else the From address (see 4.2.1) is used. The vCard EMAIL
 attribute, if present, SHOULD be the same as the reply-to address and
 may be the same as the From address.  While the vCard is the senders
 preferred address it SHOULD NOT be used to generate a reply.  Also,
 the Return-path address should not be used for replies.

Vaudreuil & Parsons Standards Track [Page 23] RFC 2421 VPIM v2 September 1998

 Support of multiple originator header fields is often not possible on
 voice messaging systems, so it may be necessary to choose only one
 when gatewaying a VPIM message to another voice message system.
 However, implementers should note that this may make it impossible to
 send error messages and replies to their proper destinations.
 In some cases, a reply message is not possible, such as with a
 message created by telephone answering (i.e. classic voice mail).  In
 this case, the From field MUST contain the special address non-mail-
 user@domain (see 4.1.2).  A null ESMTP MAIL FROM address SHOULD also
 be used in this case (see 5.1.2).  A receiving VPIM system SHOULD NOT
 offer the user the option to reply to this kind of message.

4.7 Notification Messages

 VPIM delivery status notification messages (4.4.4) MUST be sent to
 the originator of the message when any form of non-delivery of the
 subject message or its components occurs.  These error messages must
 be sent to the return path (4.2.6) if present, otherwise, the From
 (4.2.1) address may be used.
 VPIM Receipt Notification messages (4.4.5) should be sent to the
 sender specified in the Disposition-Notification-To header field
 (4.2.16), only after the message has been presented to the recipient
 or if the message has somehow been disposed of without being
 presented to the recipient (e.g. if it were deleted before playing
 it).
 VPIM Notification messages may be positive or negative, and can
 indicate delivery at the server or receipt by the client.  However,
 the notification MUST be contained in a multipart/report container
 (4.4.3) and SHOULD contain a spoken error message.
 If a VPIM system receives a message with contents that are not
 understood (see 4.3 & 4.4), its handling is a local matter.  A
 delivery status notification SHOULD be generated if the message could
 not be delivered because of unknown contents (e.g., on traditional
 voice processing systems).  In some cases, the message may be
 delivered (with a positive DSN sent) to a mailbox before the
 determination of rendering can be made.

5. Message Transport Protocol

 Messages are transported between voice mail machines using the
 Internet Extended Simple Mail Transfer Protocol (ESMTP).  All
 information required for proper delivery of the message is included
 in the ESMTP dialog.  This information, including the sender and
 recipient addresses, is commonly referred to as the message

Vaudreuil & Parsons Standards Track [Page 24] RFC 2421 VPIM v2 September 1998

 "envelope".  This information is equivalent to the message control
 block in many analog voice messaging  protocols.
 ESMTP is a general-purpose messaging protocol, designed both to send
 mail and to allow terminal console messaging.  Simple Mail Transport
 Protocol (SMTP) was originally created for the exchange of US-ASCII
 7-bit text messages.  Binary and 8-bit text messages have
 traditionally been transported by encoding the messages into a 7-bit
 text-like form.  [ESMTP] formalized an extension mechanism for SMTP,
 and subsequent RFCs have defined 8-bit text networking, command
 streaming, binary networking, and extensions to permit the
 declaration of message size for the efficient transmission of large
 messages such as multi-minute voice mail.
 The following sections list ESMTP commands, keywords, and parameters
 that are required and those that are optional for conformance to this
 profile.

5.1 ESMTP Commands

5.1.1 HELO

 Base SMTP greeting and identification of sender.  This command is not
 to be sent by compliant systems unless the more-capable EHLO command
 is not accepted.  It is included for compatibility with general SMTP
 implementations.  Compliant servers MUST implement the HELO command
 for backward compatibility but clients SHOULD NOT send it unless EHLO
 is not supported.  From [SMTP]

5.1.2 MAIL FROM (REQUIRED)

 Originating mailbox.  This address contains the mailbox to which
 errors should be sent.  VPIM implementations SHOULD use the same
 address in the MAIL FROM command as is used in the From header field.
 This address is not necessarily the same as the message Sender listed
 in the message header fields if the message was received from a
 gateway or sent to an Internet-style mailing list. From [SMTP, ESMTP]
 The MAIL FROM address SHOULD be stored in the local message store for
 the purposes of generating a delivery status notification to the
 originator. The address indicated in the MAIL FROM command SHOULD be
 passed as a local system parameter or placed in a Return-Path: line
 inserted at the beginning of a VPIM message.  From [HOSTREQ]
 Since delivery status notifications MUST be sent to the MAIL FROM
 address, the use of the null address ("<>") is often used to prevent
 looping of messages.  This null address MAY be used to note that a
 particular message has no return path (e.g. a telephone answer

Vaudreuil & Parsons Standards Track [Page 25] RFC 2421 VPIM v2 September 1998

 message).  From [SMTP]

5.1.3 RCPT TO

 Recipient's mailbox. The parameter to this command contains only the
 address to which the message should be delivered for this
 transaction.  It is the set of addresses in one or more RCPT TO
 commands that are used for mail routing. From [SMTP, ESMTP]
 Note: In the event that multiple transport connections to multiple
 destination machines are required for the same message, the set of
 addresses in a given transport connection may not match the list of
 recipients in the message header fields.

5.1.4 DATA

 Initiates the transfer of message data.  Support for this command is
 required.  Compliant implementations MUST implement the SMTP DATA
 command for backwards compatibility.  From [SMTP]

5.1.5 TURN

 Requests a change-of-roles, that is, the client that opened the
 connection offers to assume the role of server for any mail the
 remote machine may wish to send.  Because SMTP is not an
 authenticated protocol, the TURN command presents an opportunity to
 improperly fetch mail queued for another destination.  Compliant
 implementations SHOULD NOT implement the TURN command.  From [SMTP]

5.1.6 QUIT

 Requests that the connection be closed.  If accepted, the remote
 machine will reset and close the connection.  Compliant
 implementations MUST implement the QUIT command.  From [SMTP]

5.1.7 RSET

 Resets the connection to its initial state.  Compliant
 implementations MUST implement the RSET command. From [SMTP]

5.1.8 VRFY

 Requests verification that this node can reach the listed recipient.
 While this functionality is also included in the RCPT TO command,
 VRFY allows the query without beginning a mail transfer transaction.
 This command is useful for debugging and tracing problems.  Compliant
 implementations MAY implement the VRFY command.  From [SMTP] (Note
 that the implementation of VRFY may simplify the guessing of a

Vaudreuil & Parsons Standards Track [Page 26] RFC 2421 VPIM v2 September 1998

 recipient's mailbox or automated sweeps for valid mailbox addresses,
 resulting in a possible reduction in privacy.  Various implementation
 techniques may be used to reduce the threat, such as limiting the
 number of queries per session.)  From [SMTP]

5.1.9 EHLO

 The enhanced mail greeting that enables a server to announce support
 for extended messaging options.  The extended messaging modes are
 discussed in subsequent sections of this document.  Compliant
 implementations MUST implement the ESMTP command and return the
 capabilities indicated later in this memo.  From [ESMTP]

5.1.10 BDAT

 The BDAT command provides a higher efficiency alternative to the
 earlier DATA command, especially for voice. The BDAT command provides
 for native binary transport of messages. Compliant implementations
 SHOULD support binary transport using the BDAT command [BINARY].

5.2 ESMTP Keywords

 The following ESMTP keywords indicate extended features useful for
 voice messaging.

5.2.1 PIPELINING

 The "PIPELINING" keyword indicates ability of the receiving server to
 accept new commands before issuing a response to the previous
 command.  Pipelining commands dramatically improves performance by
 reducing the number of round-trip packet exchanges and makes it
 possible to validate all recipient addresses in one operation.
 Compliant implementations SHOULD support the command pipelining
 indicated by this keyword.  From [PIPE]

5.2.2 SIZE

 The "SIZE" keyword provides a mechanism by which the SMTP server can
 indicate the maximum size message supported.  Compliant servers MUST
 provide size extension to indicate the maximum size message that can
 be accepted.  Clients SHOULD NOT send messages larger than the size
 indicated by the server.  Clients SHOULD advertise SIZE= when sending
 messages to servers that indicate support for the SIZE extension.
 From [SIZE]

Vaudreuil & Parsons Standards Track [Page 27] RFC 2421 VPIM v2 September 1998

5.2.3 CHUNKING

 The "CHUNKING" keyword indicates that the receiver will support the
 high-performance binary transport mode.  Note that CHUNKING can be
 used with any message format and does not imply support for binary
 encoded messages. Compliant implementations MAY support binary
 transport indicated by this capability.  From [BINARY]

5.2.4 BINARYMIME

 The "BINARYMIME" keyword indicates that the SMTP server can accept
 binary encoded MIME messages. Compliant implementations MAY support
 binary transport indicated by this capability.  Note that support for
 this feature requires support of CHUNKING.  From [BINARY]

5.2.5 DSN

 The "DSN" keyword indicates that the SMTP server will accept explicit
 delivery status notification requests.  Compliant implementations
 MUST support the delivery notification extensions in [DRPT].

5.2.6 ENHANCEDSTATUSCODES

 The "ENHANCEDSTATUSCODES" keyword indicates that an SMTP server
 augments its responses with the enhanced mail system status codes
 [CODES].  These codes can then be used to provide more informative
 explanations of error conditions, especially in the context of the
 delivery status notifications format defined in [DSN]. Compliant
 implementations SHOULD support this capability.  From [STATUS]

5.3 ESMTP Parameters - MAIL FROM

5.3.1 BINARYMIME

 The current message is a binary encoded MIME messages.  Compliant
 implementations SHOULD support binary transport indicated by this
 parameter.  From [BINARY]

5.3.2 RET

 The RET parameter indicates whether the content of the message should
 be returned.  Compliant systems SHOULD honor a request for returned
 content. From [DRPT]

Vaudreuil & Parsons Standards Track [Page 28] RFC 2421 VPIM v2 September 1998

5.3.3 ENVID

 The ENVID keyword of the SMTP MAIL command is used to specify an
 "envelope identifier" to be transmitted along with the message and
 included in any DSNs issued for any of the recipients named in this
 SMTP transaction.  The purpose of the envelope identifier is to allow
 the sender of a message to identify the transaction for which the DSN
 was issued. Compliant implementations MAY use this parameter.  From
 [DRPT]

5.4 ESMTP Parameters - RCPT TO

5.4.1 NOTIFY

 The NOTIFY parameter indicates the conditions under which a delivery
 report should be sent. Compliant implementations MUST honor this
 request.  From [DRPT]

5.4.2 ORCPT

 The ORCPT keyword of the RCPT command is used to specify an
 "original" recipient address that corresponds to the actual recipient
 to which the message is to be delivered.  If the ORCPT esmtp-keyword
 is used, it MUST have an associated esmtp-value, which consists of
 the original recipient address, encoded according to the rules below.
 Compliant implementations MAY use this parameter.  From [DRPT]

5.5 ESMTP - SMTP Downgrading

 The ESMTP extensions suggested or required for conformance to VPIM
 fall into two categories.  The first category includes features which
 increase the efficiency of the transport system such as SIZE,
 BINARYMIME, and PIPELINING.  In the event of a downgrade to a less
 functional transport system, these features can be dropped with no
 functional change to the sender or recipient.
 The second category of features are transport extensions in support
 of new functions.  DSN and EnhancedStatusCodes provide essential
 improvements in the handling of delivery status notifications to
 bring email to the level of reliability expected of Voice Mail.  To
 ensure a consistent level of service across an intranet or the global
 Internet, it is essential that VPIM compliant ESMTP support the ESMTP
 DSN extension at all hops between a VPIM originating system and the
 recipient system. In the situation where a `downgrade' is unavoidable
 a relay hop may be forced (by the next hop) to forward a VPIM message
 without the ESMTP request for positive delivery status notification.
 It is RECOMMENDED that the downgrading system should continue to
 attempt to deliver the message, but MUST send an appropriate delivery

Vaudreuil & Parsons Standards Track [Page 29] RFC 2421 VPIM v2 September 1998

 notification to the originator, e.g. the message left an ESMTP host
 and was sent (unreliably) via SMTP.

6. Directory Address Resolution

 It is the responsibility of a VPIM system to provide the fully-
 qualified domain name (FQDN) of the recipient based on the address
 entered by the user (if the entered address is not already a FQDN).
 This would typically be an issue on systems that offered only a
 telephone user interface.  The mapping of the dialed target number to
 a routeable FQDN address allowing delivery to the destination system
 can be accomplished through implementation-specific means.
 To facilitate a local dial-by-name cache, an implementation may wish
 to populate local directories with the first and last names, as well
 as the address information extracted from received messages.  It is
 mandated that only address information from vCard attachments to VPIM
 messages be used to populate such a directory when the vCard is
 available. Addresses or names parsed from the header fields of VPIM
 messages SHOULD NOT be used to populate directories as it only
 provides partial data.  Alternatively, bilateral agreements could be
 made to allow the bulk transfer of vCards between systems.

7. IMAP

 The use of client/server desktop mailbox protocols like IMAP or POP
 to retrieve VPIM messages from a IMAP or POP message store is
 possible without any special modifications to this VPIM
 specification.  Email clients (and web browsers) typically have a
 table for mapping from MIME type to displaying application.  The
 audio/*, image/tiff and text/directory contents can be configured so
 that they invoke the correct player/recorder for rendering.  In
 addition with IMAP clients, the first multipart/mixed content (if
 present) will not appear since it is a generic part.  The user
 instead will be presented with a message that has (for example) audio
 and image contents.

8. Management Protocols

 The Internet protocols provide a mechanism for the management of
 messaging systems, from the management of the physical network
 through the management of the message queues.  SNMP should be
 supported on a compliant message machine.

Vaudreuil & Parsons Standards Track [Page 30] RFC 2421 VPIM v2 September 1998

8.1 Network Management

 The digital interface to the VM and the TCP/IP protocols MAY be
 managed.  MIB II MAY be implemented to provide basic statistics and
 reporting of TCP and IP protocol performance [MIB II].

9. Conformance Requirements

 VPIM is a messaging application which must be supported in several
 environments and be supported on differing devices.  These
 environments include traditional voice processing systems, desktop
 voice messaging systems, store and forward relays, and protocol
 translation gateways.
 In order to accommodate all environments, this document defines two
 areas of conformance:  transport and content.
 Transport conformant systems will pass VPIM messages in a store and
 forward manner with assured delivery notifications and without the
 loss of information.  It is expected that most store and forward
 Internet mail based messaging systems will be VPIM transport
 compliant.
 Content conformant systems will generate and interpret VPIM messages.
 Conformance in the generation of VPIM messages indicates that the
 restrictions of this profile are honored.  Only contents specified in
 this profile or extensions agreed to by bilateral agreement may be
 sent.  Conformance in the interpretation of VPIM messages indicates
 that all VPIM content types and constructs can be received;  that all
 mandatory VPIM content types can be decoded and presented to the
 recipient in an appropriate manner; and that any unrenderable
 contents result in the appropriate notification.
 A summary of the compliance requirements is contained in Appendix A.
 VPIM end systems are expected to be both transport and content
 conformant.  They should generate conforming content, reliably send
 it to the next hop system, receive a message, decode the message and
 present it to the user.  Voice messaging systems and protocol
 conversion gateways are considered end systems.
 Relay systems are expected to be transport compliant in order to
 receive and send conforming messages.  However, they must also create
 VPIM conforming delivery status notifications in the event of
 delivery problems.

Vaudreuil & Parsons Standards Track [Page 31] RFC 2421 VPIM v2 September 1998

 Desktop Email clients that support VPIM and are expected to be
 content conformant. Desktop email clients use various protocols and
 API's for exchanging messages with the local message store and
 message transport system.  While these clients may benefit from VPIM
 transport capabilities, specific client-server requirements are out-
 of-scope for this document.

10. Security Considerations

10.1 General Directive

 This document is a profile of existing Internet mail protocols.  To
 maintain interoperability with Internet mail, any security to be
 provided should be part of the of the Internet security
 infrastructure, rather than a new mechanism or some other mechanism
 outside of the Internet infrastructure.

10.2 Threats and Problems

 Both Internet mail and voice messaging have their own set of threats
 and countermeasures.  As such, this specification does not create any
 security issues not already existing in the profiled Internet mail
 and voice mail protocols themselves.  This section attends only to
 the set of additional threats which ensue from integrating the two
 services.

10.2.1 Spoofed sender

 The actual sender of the voice message might not be the same as that
 specified in the Sender or From header fields of the message content
 header fields or the MAIL FROM address from the SMTP envelope.  In a
 tightly constrained environment, sufficient physical and software
 controls may be able to ensure prevention of this problem.  In
 addition, the recognition of the senders voice may provide confidence
 of the sender's identity irrespective of that specified in Sender or
 From.  It should be recognized that SMTP implementations do not
 provide inherent authentication of the senders of messages, nor are
 sites under obligation to provide such authentication.

10.2.2 Unsolicited voice mail

 Assigning an Internet mail address to a voice mailbox opens the
 possibility of receiving unsolicited messages (either text or voice
 mail).  Traditionally voice mail systems operated in closed
 environments and were not susceptible to unknown senders.  Voice mail
 users have a higher expectation of mailbox privacy and may consider
 such messages as a security breach.  Many Internet mail systems are
 choosing to block all messages from unknown sources in an attempt to

Vaudreuil & Parsons Standards Track [Page 32] RFC 2421 VPIM v2 September 1998

 curb this problem.

10.2.3 Message disclosure

 Users of voice messaging systems have an expectation of a level of
 message privacy which is higher than the level provided by Internet
 mail without security enhancements.  This expectation of privacy by
 users SHOULD be preserved as much as possible.

10.3 Security Techniques

 Sufficient physical and software control may be acceptable in
 constrained environments.  Further, the profile specified in this
 document does not in any way preclude the use of any Internet object
 or channel security protocol to encrypt, authenticate, or non-
 repudiate the messages.

11. REFERENCES

 [8BIT] Klensin, J., Freed, N., Rose, M., Stefferud, E., and D.
        Crocker, "SMTP Service Extension for 8bit-MIMEtransport", RFC
        1426, February 1993.
 [ADPCM] Vaudreuil, G., and G. Parsons, "Toll Quality Voice - 32
         kbit/s ADPCM:  MIME Sub-type Registration", RFC 2422,
         September 1998.
 [AMIS-A] Audio Messaging Interchange Specifications (AMIS) - Analog
          Protocol Version 1, Issue 2, February 1992.
 [AMIS-D] Audio Messaging Interchange Specifications (AMIS) - Digital
          Protocol Version 1, Issue 3 August 1993.
 [BINARY] Vaudreuil, G., "SMTP Service Extensions for Transmission of
          Large and Binary MIME Messages", RFC 1830, October 1995.
 [CODES] Vaudreuil, G., "Enhanced Mail System Status Codes", RFC 1893,
         January 1996.
 [MIMEDIR] Howes, T., Smith, M., and F. Dawson, "A MIME Content-Type
           for Directory Information", RFC 2425, September 1998.
 [DISP] Troost, R., and S. Dorner, "Communicating Presentation
        Information in Internet Messages: The Content-Disposition
        Header", RFC 2183, August 1997.
 [DNS1] Mockapetris, P., "Domain names - implementation and
        specification", STD 13, RFC 1035, November 1987.

Vaudreuil & Parsons Standards Track [Page 33] RFC 2421 VPIM v2 September 1998

 [DNS2] Mockapetris, P., "Domain names - concepts and facilities", STD
        13, RFC 1034, November 1987.
 [DRPT] Moore, K., "SMTP Service Extensions for Delivery Status
        Notifications", RFC 1891, January 1996.
 [DSN] Moore, K., and G. Vaudreuil, "An Extensible Message Format for
       Delivery Status Notifications", RFC 1894, January 1996.
 [DUR] Vaudreuil, G., and G. Parsons, "Content Duration MIME Header
       Definition", RFC 2424, September 1998.
 [E164] CCITT Recommendation E.164 (1991), Telephone Network and ISDN
        Operation, Numbering, Routing and  Mobile Service - Numbering
        Plan for the ISDN Era.
 [ESMTP] Klensin, J., Freed, N., Rose, M., Stefferud, E., and D.
         Crocker, "SMTP Service Extensions", RFC 1869, November 1995.
 [G726] CCITT Recommendation G.726 (1990), General Aspects of Digital
        Transmission Systems, Terminal Equipment - 40, 32, 24,16
        kbit/s Adaptive Differential Pulse Code Modulation (ADPCM).
 [HOSTREQ] Braden, R., "Requirements for Internet Hosts -- Application
           and Support", STD 3, RFC 1123, October 1989.
 [LANG] Alvestrand, H., "Tags for the Identification of Languages",
        RFC 1766, March 1995.
 [MDN] Fajman, R., "An Extensible Message Format for Message
       Disposition Notifications", RFC 2298, March 1998.
 [MIB II] Rose, M., "Management Information Base for Network
          Management of TCP/IP-based internets: MIB-II", RFC 1158, May
          1990.
 [MIME1] Freed, N., and N. Borenstein, "Multipurpose Internet Mail
         Extensions (MIME) Part One: Format of Internet Message
         Bodies", RFC 2045, November 1996.
 [MIME2] Freed, N., and N. Borenstein,  "Multipurpose Internet Mail
         Extensions (MIME) Part Two: Media Types", RFC 2046, November
         1996.
 [MIME3] Moore, K., "Multipurpose Internet Mail Extensions (MIME) Part
         Three: Message Header Extensions for Non-ASCII Text", RFC
         2047, November 1996.

Vaudreuil & Parsons Standards Track [Page 34] RFC 2421 VPIM v2 September 1998

 [MIME4] Freed, N., Klensin, J., and J. Postel,  "Multipurpose
         Internet Mail Extensions (MIME) Part Four: Registration
         Procedures", RFC 2048, November 1996.
 [MIME5] Freed, N., and N. Borenstein,  "Multipurpose Internet Mail
         Extensions (MIME) Part Five: Conformance Criteria and
         Examples", RFC 2049, November 1996.
 [PIPE] Freed, N., and A. Cargille, "SMTP Service Extension for
        Command Pipelining", RFC 1854, October 1995.
 [REPORT] Vaudreuil, G., "The Multipart/Report Content Type for the
          Reporting of Mail System Administrative Messages", RFC 1892,
          January 1996.
 [REQ] Bradner, S., "Key words for use in RFCs to Indicate Requirement
       Levels", BCP 14, RFC 2119, March 1997.
 [RFC822] Crocker, D., "Standard for the Format of ARPA Internet Text
          Messages", STD 11, RFC 822, August 1982.
 [SIZE] Klensin, J., Freed, N., and K. Moore, "SMTP Service Extensions
        for Message Size Declaration", RFC 1870, November 1995.
 [SMTP] Postel, J., "Simple Mail Transfer Protocol", STD 10, RFC 821,
        August 1982.
 [STATUS] Freed, N., "SMTP Service Extension for Returning Enhanced
          Error Codes", RFC 2034, October 1996.
 [TIFF-F] Parsons, G., and J. Rafferty, "Tag Image File Format:
          Application F", RFC 2306, March 1998.
 [TIFFREG] Parsons, G., Rafferty, J., and S. Zilles, "Tag Image File
           Format: image/tiff - MIME sub-type registraion", RFC 2302,
           March 1998.
 [V-MSG] Vaudreuil, G., and G. Parsons, "VPIM Voice Message:  MIME
         Sub-type Registration", RFC 2423, September 1998.
 [VCARD] Dawson, F., and T. Howes, "vCard MIME Directory Profile", RFC
         2426, September 1998.
 [VPIM1] Vaudreuil, G., "Voice Profile for Internet Mail", RFC 1911,
         February 1996.
 [X.400] Hardcastle-Kille, S., "Mapping between X.400(1988) / ISO
         10021 and RFC 822", RFC 1327, May 1992.

Vaudreuil & Parsons Standards Track [Page 35] RFC 2421 VPIM v2 September 1998

12. Acknowledgments

 The authors would like to offer a special thanks to the Electronic
 Messaging Association (EMA), especially the members of the Voice
 Messaging Committee and the VPIM Work Group, for their support of the
 VPIM specification and the efforts they have made to ensure its
 success.
 The EMA hosts the VPIM web page at http://www.ema.org/vpim.

13. Authors' Addresses

 Glenn W. Parsons
 Northern Telecom
 P.O. Box 3511, Station C
 Ottawa, ON  K1Y 4H7
 Canada
 Phone: +1-613-763-7582
 Fax: +1-613-763-4461
 EMail: Glenn.Parsons@Nortel.ca
 Gregory M. Vaudreuil
 Lucent Technologies,
 Octel Messaging Division
 17080 Dallas Parkway
 Dallas, TX  75248-1905
 United States
 Phone/Fax: +1-972-733-2722
 EMail: GregV@Lucent.Com

Vaudreuil & Parsons Standards Track [Page 36] RFC 2421 VPIM v2 September 1998

14. Appendix A - VPIM Requirements Summary

 The following table summarizes the profile of VPIM version 2 detailed
 in this document.  Since in many cases it is not possible to simplify
 the qualifications for supporting each feature this appendix is
 informative.  The reader is recommended to read the complete
 explanation of each feature in the referenced section.  The text in
 the previous sections shall be deemed authoritative if any item in
 this table is ambiguous.
 The conformance table is separated into various columns:
   Feature - name of protocol feature (note that the indenting
             indicates a hierarchy of conformance, i.e. the
             conformance of a lower feature is only relevant if there
             is conformance to the higher feature)
   Section - reference section in main text of this document
   Area - conformance area to which each feature applies:
        C - content
        T - transport
   Status - whether the feature is mandatory, optional, or prohibited.
   The key words used in this table are to be interpreted as described
   in [REQ], though the following list gives a quick overview of the
   different degrees of feature conformance:
        Must         - mandatory
        Should       - required in the absence of a compelling
                       need to omit.
        May          - optional
        Should not   - prohibited in the absence of a compelling
                       need.
        Must not     - prohibited
   Footnote - special comment about conformance for a particular
   feature

Vaudreuil & Parsons Standards Track [Page 37] RFC 2421 VPIM v2 September 1998

                      VPIM version 2 Conformance
                                                      | | | | |S| |
                                           |          | | | | |H| |F
                                           |          | | | | |O|M|o
                                           |          | | |S| |U|U|o
                                           |          | | |H| |L|S|t
                                           |          |A|M|O| |D|T|n
                                           |          |R|U|U|M| | |o
                                           |          |E|S|L|A|N|N|t
                                           |          |A|T|D|Y|O|O|t
FEATURE                                    |SECTION   | | | | |T|T|e
-------------------------------------------|----------|-|-|-|-|-|-|-
                                           |          | | | | | | |
Message Addressing Formats:                |          | | | | | | |
  Use DNS host names                       |4.1       |C|x| | | | |
  Use only numbers in mailbox IDs          |4.1.1     |C| |x| | | |
  Use alpha-numeric mailbox IDs            |4.1.1     |C| | |x| | |
  Support of postmaster@domain             |4.1.2     |C|x| | | | |
  Support of non-mail-user@domain          |4.1.2     |C| |x| | | |
  Support of distribution lists            |4.1.3     |C| |x| | | |
                                           |          | | | | | | |
Message Header Fields:                     |          | | | | | | |
  Encoding outbound messages               |          | | | | | | |
    From                                   |4.2.1     |C|x| | | | |
      Addition of text name                |4.2.1     |C| |x| | | |
    To                                     |4.2.2     |C|x| | | | |1
    cc                                     |4.2.3     |C| |x| | | |1
    Date                                   |4.2.4     |C|x| | | | |
    Sender                                 |4.2.5     |C| | |x| | |
    Return-Path                            |4.2.6     |C| | |x| | |
    Message-id                             |4.2.7     |C|x| | | | |
    Reply-To                               |4.2.8     |C| | | |x| |
    Received                               |4.2.9     |C|x| | | | |
    MIME Version: 1.0 (Voice 2.0)          |4.2.10    |C| |x| | | |
    Content-Type                           |4.2.11    |C|x| | | | |
    Content-Transfer-Encoding              |4.2.12    |C|x| | | | |
    Sensitivity                            |4.2.13    |C| | |x| | |
    Importance                             |4.2.14    |C| | |x| | |
    Subject                                |4.2.15    |C| |x| | | |
    Disposition-notification-to            |4.2.16    |C| | |x| | |
    Disposition-notification-options       |4.2.17    |C| | |x| | |
    Other Headers                          |4.2       |C| | |x| | |
                                           |          | | | | | | |

Vaudreuil & Parsons Standards Track [Page 38] RFC 2421 VPIM v2 September 1998

                                                      | | | | |S| |
                                           |          | | | | |H| |F
                                           |          | | | | |O|M|o
                                           |          | | |S| |U|U|o
                                           |          | | |H| |L|S|t
                                           |          |A|M|O| |D|T|n
                                           |          |R|U|U|M| | |o
                                           |          |E|S|L|A|N|N|t
                                           |          |A|T|D|Y|O|O|t
FEATURE                                    |SECTION   | | | | |T|T|e
-------------------------------------------|----------|-|-|-|-|-|-|-
  Detection & Decoding inbound messages    |          | | | | | | |
    From                                   |4.2.1     |C|x| | | | |
      Present text personal name           |4.2.1     |C| | |x| | |
    To                                     |4.2.2     |C|x| | | | |
    cc                                     |4.2.3     |C| | |x| | |
    Date                                   |4.2.4     |C|x| | | | |
      Conversion of Date to local time     |4.2.4     |C| |x| | | |
    Sender                                 |4.2.5     |C| | |x| | |
    Return-Path                            |4.2.6     |C| | |x| | |
    Message ID                             |4.2.7     |C|x| | | | |
    Reply-To                               |4.2.8     |C| |x| | | |
    Received                               |4.2.9     |C| | |x| | |
    MIME Version: 1.0 (Voice 2.0)          |4.2.10    |C| |x| | | |
    Content Type                           |4.2.11    |C|x| | | | |
    Content-Transfer-Encoding              |4.2.12    |C|x| | | | |
    Sensitivity                            |4.2.13    |C|x| | | | |2
    Importance                             |4.2.14    |C| | |x| | |
    Subject                                |4.2.15    |C| | |x| | |
    Disposition-notification-to            |4.2.16    |C| | |x| | |
    Disposition-notification-options       |4.2.17    |C| | |x| | |
    Other Headers                          |4.2       |C|x| | | | |3
                                           |          | | | | | | |
Message Content Encoding:                  |          | | | | | | |
  Encoding outbound audio/fax contents     |          | | | | | | |
    7BIT                                   |4.3       |C| | | | |x|
    8BIT                                   |4.3       |C| | | | |x|
    Quoted Printable                       |4.3       |C| | | | |x|
    Base64                                 |4.3       |C|x| | | | |4
    Binary                                 |4.3       |C| |x| | | |5
  Detection & decoding inbound messages    |          | | | | | | |
    7BIT                                   |4.3       |C|x| | | | |
    8BIT                                   |4.3       |C|x| | | | |
    Quoted Printable                       |4.3       |C|x| | | | |
    Base64                                 |4.3       |C|x| | | | |
    Binary                                 |4.3       |C|x| | | | |5
                                           |          | | | | | | |

Vaudreuil & Parsons Standards Track [Page 39] RFC 2421 VPIM v2 September 1998

                                                      | | | | |S| |
                                           |          | | | | |H| |F
                                           |          | | | | |O|M|o
                                           |          | | |S| |U|U|o
                                           |          | | |H| |L|S|t
                                           |          |A|M|O| |D|T|n
                                           |          |R|U|U|M| | |o
                                           |          |E|S|L|A|N|N|t
                                           |          |A|T|D|Y|O|O|t
FEATURE                                    |SECTION   | | | | |T|T|e
-------------------------------------------|----------|-|-|-|-|-|-|-
Message Content Types:                     |          | | | | | | |
  Inclusion in outbound messages           |          | | | | | | |
    Multipart/Voice-Message                |4.3.1     |C|x| | | | |
      Message/RFC822                       |4.3.2     |C| | |x| | |
      Text/Directory                       |4.3.3     |C| |x| | | |
        include TEL, EMAIL, VERSION        |4.3.3     |C|x| | | | |
        include ROLE, SOUND, N, REV        |4.3.3     |C| |x| | | |
        only one voice type per level      |4.3.3     |C|x| | | | |
      Audio/32KADPCM                       |4.3.4     |C|x| | | | |
        Content-Description                |4.3.4.1   |C| | |x| | |
        Content-Disposition                |4.3.4.2   |C|x| | | | |
        Content-Duration                   |4.3.4.3   |C| | |x| | |
        Content-Langauge                   |4.3.4.4   |C| | |x| | |
      Image/tiff; application=faxbw        |4.3.5     |C| | |x| | |
      Audio/* or Image/* (other encodings) |4.3.6     |C| | |x| | |
    Multipart/Mixed                        |4.4.1     |C| | |x| | |
    Text/plain                             |4.4.2     |C| | | |x| |
    Multipart/Report                       |4.4.3     |C|x| | | | |
       human-readable part is voice        |4.4.3     |C| |x| | | |
       human-readable part is text         |4.4.3     |C| | |x| | |
    Message/delivery-status                |4.4.4     |C|x| | | | |
    Message/disposition-notification       |4.4.5     |C| |x| | | |
    Other contents                         |4.4       |C| | | |x| |6
                                           |          | | | | | | |
  Detection & decoding in inbound messages |          | | | | | | |
    Multipart/Voice-Message                |4.3.1     |C|x| | | | |
      Message/RFC822                       |4.3.2     |C|x| | | | |
      Text/Directory                       |4.3.3     |C| |x| | | |
        recognize TEL, EMAIL, VERSION      |4.3.3     |C|x| | | | |
        recognize ROLE, SOUND, N, REV      |4.3.3     |C| |x| | | |
      Audio/32KADPCM                       |4.3.4     |C|x| | | | |
        Content-Description                |4.3.4.1   |C| | |x| | |
        Content-Disposition                |4.3.4.2   |C| |x| | | |
        Content-Duration                   |4.3.4.3   |C| | |x| | |
        Content-Langauge                   |4.3.4.4   |C| | |x| | |
      Image/tiff; application=faxbw        |4.3.5     |C| |x| | | |
        send NDN if unable to render       |4.3.5     |C|x| | | | |7

Vaudreuil & Parsons Standards Track [Page 40] RFC 2421 VPIM v2 September 1998

      Audio/* or Image/* (other encodings) |4.3.6     |C| | |x| | |
    Multipart/Mixed                        |4.4.1     |C|x| | | | |
    Text/plain                             |4.4.2     |C|x| | | | |
      send NDN if unable to render         |4.4.2     |C|x| | | | |

Vaudreuil & Parsons Standards Track [Page 41] RFC 2421 VPIM v2 September 1998

                                          |           | | | | |S| |
                                          |           | | | | |H| |F
                                          |           | | | | |O|M|o
                                          |           | | |S| |U|U|o
                                          |           | | |H| |L|S|t
                                          |           |A|M|O| |D|T|n
                                          |           |R|U|U|M| | |o
                                          |           |E|S|L|A|N|N|t
                                          |           |A|T|D|Y|O|O|t
FEATURE                                   |SECTION    | | | | |T|T|e
------------------------------------------|-----------|-|-|-|-|-|-|-
                                          |           | | | | | | |
   Multipart/Report                       |4.4.3      |C|x| | | | |
     human-readable part is voice         |4.4.3      |C| |x| | | |
     human-readable part is text          |4.4.3      |C|x| | | | |
    Message/delivery-status               |4.4.4      |C|x| | | | |
    Message/disposition-notification      |4.4.5      |C| |x| | | |
    Other contents                        |4.4        |C| | | |x| |6
      send NDN if unable to render        |4.4        |C| |x| | | |
                                          |           | | | | | | |
  Forwarded Messages                      |           | | | | | | |
    use Message/RFC822 construct          |4.5        |C| |x| | | |
    simulate headers if none available    |4.5        |C| |x| | | |
                                          |           | | | | | | |
  Reply Messages                          |           | | | | | | |
    send to Reply-to, else From address   |4.6        |C|x| | | | |
    do not send to non-mail-user          |4.6        |C|x| | | | |
                                          |           | | | | | | |
  Notifications                           |           | | | | | | |
    use multipart/report format           |4.7        |C|x| | | | |
    always send error on non-delivery     |4.7        |C| |x| | | |
                                          |           | | | | | | |
Message Transport Protocol:               |           | | | | | | |
  ESMTP Commands                          |           | | | | | | |
    HELO                                  |5.1.1      |T|x| | | | |
    MAIL FROM                             |5.1.2      |T|x| | | | |
      support null address                |5.1.2      |T|x| | | | |
    RCPT TO                               |5.1.3      |T|x| | | | |
    DATA                                  |5.1.4      |T|x| | | | |
    TURN                                  |5.1.5      |T| | | | |x|
    QUIT                                  |5.1.6      |T|x| | | | |
    RSET                                  |5.1.7      |T|x| | | | |
    VRFY                                  |5.1.8      |T| | |x| | |
    EHLO                                  |5.1.9      |T|x| | | | |
    BDAT                                  |5.1.10     |T| | |x| | |5

Vaudreuil & Parsons Standards Track [Page 42] RFC 2421 VPIM v2 September 1998

                                                      | | | | |S| |
                                           |          | | | | |H| |F
                                           |          | | | | |O|M|o
                                           |          | | |S| |U|U|o
                                           |          | | |H| |L|S|t
                                           |          |A|M|O| |D|T|n
                                           |          |R|U|U|M| | |o
                                           |          |E|S|L|A|N|N|t
                                           |          |A|T|D|Y|O|O|t
FEATURE                                    |SECTION   | | | | |T|T|e
-------------------------------------------|----------|-|-|-|-|-|-|-
                                           |          | | | | | | |
  ESMTP Keywords & Parameters             |           | | | | | | |
    PIPELINING                            |5.2.1      |T| |x| | | |
    SIZE                                  |5.2.2      |T|x| | | | |
    CHUNKING                              |5.2.3      |T| | |x| | |
    BINARYMIME                            |5.2.4,5.3.1|T| | |x| | |
    DSN                                   |5.2.5      |T|x| | | | |
    ENHANCEDSTATUSCODES                   |5.2.6      |T| |x| | | |
    RET                                   |5.3.2      |T| |x| | | |
    ENVID                                 |5.3.3      |T| | |x| | |
    NOTIFY                                |5.4.1      |T|x| | | | |
    ORCPT                                 |5.4.2      |T| | |x| | |
                                          |           | | | | | | |
  ESMTP-SMTP Downgrading                   |          | | | | | | |
    send delivery report upon downgrade    |
                                           |          | | | | | | |
Directory Address Resolution               |          | | | | | | |
  provide facility to resolve addresses    |6         |C| |x| | | |
  use vCards to populate local directory   |6         |C| |x| | | |8
  use headers to populate local directory  |6         |C| | | |x| |
                                           |          | | | | | | |
Management Protocols:                      |          | | | | | | |
  Network management                       |8.1       |T| ||x| | |
-------------------------------------------|----------|-|-|-|-|-|-|-
Footnotes:
1.  MUST NOT include if all recipients are not known or resolvable.
2.  If a sensitive message is received by a system that does not
   support sensitivity, then it MUST be returned to the originator
   with an appropriate error notification.  Also, a received
   sensitive message MUST NOT be forwarded to anyone.
3.  If the addtional header fields are not understood they MAY be
   ignored
4.  When binary transport is not available
5.  When binary transport is available

Vaudreuil & Parsons Standards Track [Page 43] RFC 2421 VPIM v2 September 1998

6.  Other un-profiled contents must only be sent by bilateral
   agreement.
7.  If the content cannot be presented in some form, the entire
   message MUST be returned with a negative delivery status
   notification.
8.  When the vCard is present in a message

Vaudreuil & Parsons Standards Track [Page 44] RFC 2421 VPIM v2 September 1998

15. Appendix B - Example Voice Messages

 The following message is a full-featured message addressed to two
 recipients. The message includes the sender's spoken name and a short
 speech segment.  The message is marked as important and private.
 To: +19725551212@vm1.mycompany.com
 To: +16135551234@VM1.mycompany.com
 From: "Parsons, Glenn" <12145551234@VM2.mycompany.com>
 Date: Mon, 26 Aug 93 10:20:20 -0700 (CDT)
 MIME-Version: 1.0  (Voice 2.0)
 Content-type: Multipart/Voice-Message; Version=2.0;
   Boundary="MessageBoundary"
 Content-Transfer-Encoding: 7bit
 Message-ID: 123456789@VM2.mycompany.com
 Sensitivity: Private
 Importance: High
  1. -MessageBoundary

Content-type: Audio/32KADPCM

 Content-Transfer-Encoding: Base64
 Content-Disposition: inline; voice=Originator-Spoken-Name
 Content-Language: en-US
 Content-ID: part1@VM2-4321
 glslfdslsertiflkTfpgkTportrpkTpfgTpoiTpdadasssdasddasdasd
 (This is a sample of the base-64 Spoken Name data)
 fgdhgddlkgpokpeowrit09==
  1. -MessageBoundary

Content-type: Audio/32KADPCM

 Content-Transfer-Encoding: Base64
 Content-Description: Brand X Voice Message
 Content-Disposition: inline; voice=Voice-Message; filename=msg1.726
 Content-Duration: 25
 iIiIiIjMzN3czdze3s7d7fwfHhcvESJVe/4yEhLz8/FOQjVFRERCESL/zqrq
 (This is a sample of the base64 message data) zb8tFdLTQt1PXj
 u7wjOyRhws+krdns7Rju0t4tLF7cE0K0MxOTOnRW/Pn30c8uHi9==
  1. -MessageBoundary

Content-type: text/directory; charset=us-ascii; profile=vCard

 Content-Transfer-Encoding: 7bit
 BEGIN:VCARD
 N:Parsons;Glenn;;Mr.;
 EMAIL;TYPE=INTERNET:+12145551234@VM2.mycompany.com
 TEL:+1-217-555-1234

Vaudreuil & Parsons Standards Track [Page 45] RFC 2421 VPIM v2 September 1998

 SOUND;TYPE=32KADPCM;ENCODING=URI: CID:<part1@VM2-4321>
 REV:19951031T222710Z
 VERSION: 3.0
 END:VCARD
  1. -MessageBoundary_
 The following message is a forwarded single segment voice.  Both the
 forwarded message and the forwarding message contain VCARDs with
 spoken names.
  To: +12145551212@vm1.mycompany.com
  From: "Vaudreuil, Greg" <+19725552345@VM2.mycompany.com>
  Date: Mon, 26 Aug 93 10:20:20 -0700 (CDT)
  MIME-Version: 1.0  (Voice 2.0)
  Content-type: Multipart/Voice-Message; Version=2.0;
    Boundary="MessageBoundary"
  Content-Transfer-Encoding: 7bit
  Message-ID: ABCD-123456789@VM2.mycompany.com
  1. -MessageBoundary

Content-type: Audio/32KADPCM

  Content-Transfer-Encoding: Base64
  Content-Disposition: inline; voice=Originator-Spoken-Name
  Content-Language: en-US
  Content-ID: part3@VM2-4321
  glslfdslsertiflkTfpgkTportrpkTpfgTpoiTpdadasssdasddasdasd
  (This is a sample of the base-64 Spoken Name data)
  fgdhgd dlkgpokpeowrit09==
  1. -MessageBoundary

Content-type: Audio/32KADPCM

  Content-Description: Forwarded Message Annotation
  Content-Disposition: inline; voice=Voice-Message
  Content-Transfer-Encoding: Base64
  glslfdslsertiflkTfpgkTportrpkTpfgTpoiTpdadasssdasddasdasd
  (This is the voiced introductory remarks encoded in base64)
  jrgoij3o45itj09fiuvdkjgWlakgQ93ijkpokfpgokQ90gQ5tkjpokfgW
  dlkgpokpeowrit09==
  1. -MessageBoundary

Content-type: Message/RFC822

  Content-Transfer-Encoding: 7bit
  To: +19725552345@VM2.mycompany.com

Vaudreuil & Parsons Standards Track [Page 46] RFC 2421 VPIM v2 September 1998

  From: "Parsons, Glenn, W." <+16135551234@VM1.mycompany.com>
  Date: Mon, 26 Aug 93 8:23:10 -0500 (EST)
  Content-type: Multipart/Voice-Message; Version=2.0;
    Boundary="MessageBoundary2"
  Content-Transfer-Encoding: 7bit
  MIME-Version: 1.0  (Voice 2.0)
  1. -MessageBoundary2

Content-type: Audio/32KADPCM

  Content-Transfer-Encoding: Base64
  Content-Disposition: inline; voice=Originator-Spoken-Name
  Content-Language: en-US
  Content-ID: part6@VM2-4321
  glslfdslsertiflkTfpgkTportrpkTpfgTpoiTpdadasssdasddasdasd
  (This is a sample of the base-64 Spoken Name data) fgdhgd
   dlkgpokpeowrit09==
  1. -MessageBoundary2

Content-type: Audio/32KADPCM

  Content-Disposition: inline; voice=Voice-Message
  Content-Transfer-Encoding: Base64
  glslfdslsertiflkTfpgkTportrpkTpfgTpoiTpdadasssdasddasdasd
  (This is the original message audio data) fgwersdfmniwrjj
  jrgoij3o45itj09fiuvdkjgWlakgQ93ijkpokfpgokQ90gQ5tkjpokfgW
  dlkgpokpeowrit09==
  1. -MessageBoundary2

Content-type: text/directory; charset=us-ascii

  Content-Transfer-Encoding: 7bit
  BEGIN:VCARD
  N:Parsons;Glenn;W;Mr.;
  EMAIL;TYPE=INTERNET:+16135551234@VM2.mycompany.com
  TEL:+1-613-555-1234
  SOUND;TYPE=32KADPCM;ENCODING=URI: CID:<part6@VM2-4321>
  REV:19951031T222710Z
  END:VCARD
  1. -MessageBoundary2–
  1. -MessageBoundary

Content-type: text/directory; charset=us-ascii

  Content-Transfer-Encoding: 7bit
  BEGIN:VCARD
  N:Vaudreuil;Greg;;Mr.;

Vaudreuil & Parsons Standards Track [Page 47] RFC 2421 VPIM v2 September 1998

  SOUND;TYPE=32KADPCM;ENCODING=URI: CID:<part3@VM2-4321>
  EMAIL;TYPE=INTERNET,VPIM:+19725552345@VM2.mycompany.com
  TEL:+1-972-555-2345
  REV:19951031T222710Z
  VERSION: 3.0
  END:VCARD
  1. -MessageBoundary–
  The following example is for a message returned to the sender by a
  VPIM gateway at VM1.company.com for a mailbox which does not exist.
  Date: Thu, 7 Jul 1994 17:16:05 -0400
  From: Mail Delivery Subsystem <MAILER-DAEMON@vm.company.com>
  Message-Id: <199407072116.RAA14128@vm1.company.com>
  Subject: Returned voice message
  To: 2175552345@VM2.mycompany.com
  MIME-Version: 1.0 (Voice 2.0)
  Content-Type: multipart/report; report-type=delivery-status;
    boundary="RAA14128.773615765/VM1.COMPANY.COM"
  1. -RAA14128.773615765/VM1.COMPANY.COM

Content-type: Audio/32KADPCM

  Content-Description: Spoken Delivery Status Notification
  Content-Disposition: inline; voice= Voice-Message-Notification
  Content-Transfer-Encoding: Base64
  glslfdslsertiflkTfpgkTportrpkTpfgTpoiTpdadadffsssddasdasd
  (This is a voiced description of the error in base64)
  jrgoij3o45itj09fiuvdkjgWlakgQ93ijkpokfpgokQ90gdffkjpokfgW
  dlkgpokpeowrit09==
  1. -RAA14128.773615765/VM1.COMPANY.COM

Content-type: message/delivery-status

  Reporting-MTA: dns; vm1.company.com
  Original-Recipient: rfc822; 2145551234@VM1.mycompany.com
  Final-Recipient: rfc822; 2145551234@VM1.mycompany.com
  Action: failed
  Status: 5.1.1 (User does not exist)
  Diagnostic-Code: smtp; 550 Mailbox not found
  Last-Attempt-Date: Thu, 7 Jul 1994 17:15:49 -0400
  1. -RAA14128.773615765/VM1.COMPANY.COM

content-type: message/rfc822

  [original VPIM message goes here]

Vaudreuil & Parsons Standards Track [Page 48] RFC 2421 VPIM v2 September 1998

  1. -RAA14128.773615765/VM1.COMPANY.COM–
  The following example is for a receipt notification sent to the
  original sender for a message which has been played.  This
  delivered VPIM message was received by a corporate gateway and
  relayed to a unified mailbox.
  Date: Thu, 7 Jul 1994 17:16:05 -0400
  From: "Greg Vaudreuil" <22722@vm.company.com>
  Message-Id: <199407072116.RAA14128@exchange.company.com>
  Subject: Voice message played
  To: 2175552345@VM2.mycompany.com
  MIME-Version: 1.0 (Voice 2.0)
  Content-Type: multipart/report;
    Report-type=disposition-notification;
    Boundary="RAA14128.773615765/EXCHANGE.COMPANY.COM"
  1. -RAA14128.773615765/EXCHANGE.COMPANY.COM

Content-type: Audio/32KADPCM

  Content-Description: Spoken Disposition Notification
  Content-Disposition: inline; voice= Voice-Message-Notification
  Content-Transfer-Encoding: Base64
  glslfdslsertiflkTfpgkTportrpkTpfgTpoiTpdadadffsssddasdasd
  (Voiced description of the disposition action in base64)
  jrgoij3o45itj09fiuvdkjgWlakgQ93ijkpokfpgokQ90gdffkjpokfgW
  dlkgpokpeowrit09==
  1. -RAA14128.773615765/EXCHANGE.COMPANY.COM

Content-type: message/disposition-notification

  Reporting-UA: gregs-laptop.dallas.company.com (Unified FooMail 3.0)
  Original-Recipient: rfc822;22722@vm.company.com
  Final-Recipient: rfc822;Greg.Vaudreuil@foomail.company.com
  Original-Message-ID: <199509192301.12345@vm2.mycompany.com >
  Disposition: manual-action/MDN-sent-automatically; displayed
  1. -RAA14128.773615765/EXCHANGE.COMPANY.COM

Content-type: message/rfc822

  [original VPIM message goes here]
  1. -RAA14128.773615765/EXCHANGE.COMPANY.COM–

Vaudreuil & Parsons Standards Track [Page 49] RFC 2421 VPIM v2 September 1998

16. Appendix C - Example Error Voice Processing Error Codes

 The following common voice processing errors and their corresponding
 status codes are given as examples.  Text after the error codes are
 intended only for reference to describe the error code.
 Implementations should provide implementation specific informative
 comments after the error code rather than the text below.
 Error condition                 RFC 1893 Error codes
 -----------------------------   --------------------------------
 Analog delivery failed          4.4.0 Persistent connection error
 because remote system is busy         - other
 Analog delivery failed          4.4.1 Persistent protocol error
 because remote system is              - no answer from host
 ring-no-answer
 Remote system did not answer    5.5.5 Permanent protocol error
 AMIS-Analog handshake ("D" in         - wrong version
 response to "C" at connect
 time)
 Mailbox does not exist          5.1.1 Permanent mailbox error
                                       - does not exist
 Mailbox full or over quota      4.2.2 Persistent mailbox error
                                       - full
 Disk full                       4.3.1 Persistent system error
                                       - full
 Command out of sequence         5.5.1 Permanent protocol error
                                       - invalid command
 Frame Error                     5.5.2 Permanent protocol error
                                       - syntax error
 Mailbox does not support FAX    5.6.1 Permanent media error
                                       - not supported
 Mailbox does not support TEXT   5.6.1 Permanent media error
                                       - not supported
 Sender is not authorized        5.7.1 Permanent security error
                                       - sender not authorized

Vaudreuil & Parsons Standards Track [Page 50] RFC 2421 VPIM v2 September 1998

 Message marked private, but     5.3.3 Permanent system error
 system is not private capable         - not feature capable

17. Appendix D - Example Voice Processing Disposition Types

 The following common voice processing disposition conditions and
 their corresponding MDN Disposition (which contains the disposition
 mode, type and modifier, if applicable) are given as examples.
 Implementers should refer to [MDN] for a full description of the
 format of message disposition notifications.
 Notification event               MDN Disposition mode, type & modifier
 ------------------------------   -------------------------------------
 Message played by recipient,    manual-action/MDN-sent-automatically;
 receipt automatically returned  displayed
 Message deleted from mailbox    manual-action/MDN-sent-automatically;
 by user without listening       deleted
 Message cleared when mailbox    manual-action/MDN-sent-automatically;
 deleted by admin                deleted/mailbox-terminated
 Message automatically deleted   automatic-action/
 when older than administrator   MDN-sent-automatically; deleted/
 set threshold                   expired
 Message processed, however      manual-action/MDN-sent-automatically;
 audio encoding unknown -        processed/error
 unable to play to user          Error: unknown audio encoding

Vaudreuil & Parsons Standards Track [Page 51] RFC 2421 VPIM v2 September 1998

18. Appendix E - IANA Registrations

18.1 vCard EMAIL Type Definition for VPIM

 To: ietf-mime-directory@imc.org
 Subject: Registration of new parameter for text/directory MIME type
 EMAIL
 Type name: EMAIL
 Type purpose: To specify the electronic mail address for
 communication with the object the vCard represents (defined in
 [VCARD]).
 Type encoding: 8bit
 Type value: A single text value.
 Type special notes: The type may include the type parameter "TYPE" to
 specify the format or preference of the electronic mail address. The
 TYPE parameter values previously defined include: "internet" to
 indicate an Internet addressing type, "x400" to indicate a X.400
 addressing type and "pref" to indicate a preferred-use email address
 when more than one is specified. The value of "vpim" is defined to
 indicate that the address specified supports VPIM messages.  Other
 IANA registered address type may also be specified. The default email
 type is "internet". A non-standard value may also be specified.
 Type example:
               EMAIL;TYPE=internet,vpim:jqpublic@xyz.dom1.com

18.2 Voice Content-Disposition Parameter Definition

 To: IANA@IANA.ORG
 Subject: Registration of new Content-Disposition parameter
 Content-Disposition parameter name: voice
 Allowable values for this parameter:
        Voice-Message - the primary voice message,
        Voice-Message-Notification - a spoken delivery notification
          or spoken disposition notification,
        Originator-Spoken-Name - the spoken name of the originator,

Vaudreuil & Parsons Standards Track [Page 52] RFC 2421 VPIM v2 September 1998

        Recipient-Spoken-Name - the spoken name of the recipient if
          available to the originator and present if there is ONLY one
          recipient,
        Spoken-Subject- the spoken subject of the message, typically
          spoken by the originator
 Description:
 In order to distinguish between the various types of audio contents
 in a VPIM voice message a new disposition parameter "voice" is
 defined with the preceding values to be used as appropriate. Note
 that there SHOULD only be one instance of each of these types of
 audio contents per message level.  Additional instances of a given
 type (i.e., parameter value) may occur within an attached forwarded
 voice message.

Vaudreuil & Parsons Standards Track [Page 53] RFC 2421 VPIM v2 September 1998

19. Appendix F - Change History: RFC 1911 to this Document

 The updated profile in this document is based on the experience of a
 proof of concept demonstration of VPIM at EMA'96 in April 1996 and a
 subsequent demonstration of products at EMA'97 in April 1997.  This
 version of the profile is significantly different from the previous
 described in [VPIM1].  The changes are categorized as general,
 content, transport and compliance.  They are detailed below:
 1. General
  1. All definitions are now contained in separate documents that are

referenced by this profile. The new documents include:

  1. a refined multipart/voice-message definition
  1. a refined (i.e., added nibble order) audio/32KADPCM definition
  1. the definitions of TIFF-F and image/tiff for fax images
  1. the Content-Duration definition
  1. Changed the Voice version to 2.0
  1. Added Table of Contents and more examples
  1. Various editorial updates to improve readability
  1. Added more security considerations
 2. Content
  1. Modified multipart/voice-message content type by dropping the

positional dependence of contents while restricting its contents to

   voice message specific content types
  1. Explicitly indicated other contents that may be present ina

multipart/mixed content type

  1. Explicitly defined the forwarding model using message/RFC822
  1. Explained the use of reply-to and from header fields for

addressing message replies

  1. Deprecated the special "loopback" address because of security

concerns and its use only for testing

Vaudreuil & Parsons Standards Track [Page 54] RFC 2421 VPIM v2 September 1998

  1. Defined the non-mail-user reserved address to support the case in

which replies to the originator are not possible

  1. Eliminated the text name in the "To" and "CC" header fields.

Deprecated ordering of text names in the "From" header.

  1. Added support for facsimile using TIFF-F in an image/tiff;

application=faxbw content type

  1. Profiled vCard in the text/directory body part for transport of

directory information about the originator

  1. Loosened text restriction
  1. Added additional details on delivery and receipt notifications
  1. Added support for message disposition notifications, also known

as receipt notifications.

  1. Added suggested addressing formats
  1. Described handling of private messages
  1. Described the handling of non-profiled contents in VPIM messages
  1. Described the use of Content-Disposition to semantically identify

audio contents

 3. Transport
  1. Moved binary support to optional
  1. Added optional ESMTP keywords for return of content, enhanced

status codes, original recipient, and envelope ID

  1. Described use of null MAIL FROM address
 4. Compliance
  1. Added an explicit section on conformance specifying conformance

to content or transport

  1. Improved conformance table in Appendix A

Vaudreuil & Parsons Standards Track [Page 55] RFC 2421 VPIM v2 September 1998

20. Full Copyright Statement

 Copyright (C) The Internet Society (1998).  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.

Vaudreuil & Parsons Standards Track [Page 56]

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