GENWiki

Premier IT Outsourcing and Support Services within the UK

User Tools

Site Tools

Problem, Formatting or Query -  Send Feedback

Was this page helpful?-10+1


rfc:rfc3801

Network Working Group G. Vaudreuil Request for Comments: 3801 Lucent Technologies Obsoletes: 2421 G. Parsons Category: Standards Track Nortel Networks

                                                             June 2004
       Voice Profile for Internet Mail - version 2 (VPIMv2)

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 (2004).

Abstract

 This document specifies a restricted profile of the Internet
 multimedia messaging protocols for use between voice processing
 server platforms.  The profile is referred to as the Voice Profile
 for Internet Mail (VPIM) in this document.  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
 conforming systems.
 This document obsoletes RFC 2421 and describes version 2 of the
 profile with greater precision.  No protocol changes were made in
 this revision. A list of changes from RFC 2421 are noted in Appendix
 F.  Appendix A summarizes the protocol profiles of this version of
 VPIM.

Vaudreuil & Parsons Standards Track [Page 1] RFC 3801 VPIMv2 June 2004

Table of Contents

 1.   Introduction...................................................3
      1.1.  Voice Messaging System Limitations.......................3
      1.2.  Design Goals.............................................4
      1.3.  Applicability for VPIM...................................5
 2.   Requirements Language..........................................5
 3.   Protocol Restrictions..........................................6
 4.   Voice Message Interchange Format...............................6
      4.1.  VPIM Message Addressing Formats..........................7
      4.2.  Message Header Fields....................................9
      4.3.  MIME Audio Content Descriptions.........................17
      4.4.  Voice Message Content Types.............................19
      4.5.  Other MIME Contents.....................................23
      4.6.  Delivery Status Notification (DSN)......................25
      4.7.  Message Disposition Notification (MDN)..................26
      4.8.  Forwarded Messages......................................26
      4.9.  Reply Messages..........................................27
 5.   Message Transport Protocol....................................27
      5.1.  Base SMTP Protocol......................................28
      5.2.  SMTP Service Extensions.................................28
      5.3.  ESMTP - SMTP Downgrading................................30
 6.   Directory Address Resolution..................................30
 7.   Management Protocols..........................................30
      7.1.  Network Management......................................31
 8.   Conformance Requirements......................................31
 9.   Security Considerations.......................................32
      9.1.  General Directive.......................................32
      9.2.  Threats and Problems....................................32
      9.3.  Security Techniques.....................................33
 10.  Normative References..........................................33
 11.  Acknowledgments...............................................36
 12.  Appendix A - VPIM Requirements Summary........................37
 13.  Appendix B - Example Voice Messages...........................43
 14.  Appendix C - Example Error Voice Processing Error Codes.......49
 15.  Appendix D - Example Voice Processing Disposition Types.......50
 16.  Appendix E - IANA Registrations...............................50
      16.1.  Voice Content-Disposition Parameter Definition.........51
      16.2.  Multipart/Voice-Message MIME Media Type Definition.....51
 17.  Appendix F - Change History: RFC 2421 (VPIM V2) To This Doc...53
 18.  Authors' Addresses............................................54
 19.  Full Copyright Statement......................................55

Vaudreuil & Parsons Standards Track [Page 2] RFC 3801 VPIMv2 June 2004

1. Introduction

 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.
 Voice messaging evolved as telephone answering service into a full
 send, receive, and forward messaging paradigm with unique message
 features, semantics and usage patterns.  Voice messaging was
 introduced on special purpose computers that interface to a telephone
 switch and provide call answering and voice messaging services.
 Traditionally, messages sent from one voice messaging system to
 another were transported using analog networking protocols based on
 DTMF signaling and analog voice playback. As the demand for
 networking increases, there was a need for a standard high-quality
 digital protocol to connect these machines.  VPIM has successfully
 demonstrated its usefulness as this new standard.  VPIM is widely
 implemented and is seeing deployment in customer networks.  This
 document clarifies ambiguities found in the earlier specification and
 is consistent with implementation practice.  The profile is referred
 to as Voice Profile for Internet Mail (VPIM) in this document.
 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 conforming systems.
 This document obsoletes RFC 2421 and describes VPIM version 2 of with
 greater precision.  No protocol changes were made in this revision.
 A list of changes from RFC 2421 are noted in Appendix F.  Appendix A
 summarizes the protocol profiles of this version of VPIM.

1.1. Voice Messaging System Limitations

 The following are typical limitations of voice messaging platforms
 that 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 3801 VPIMv2 June 2004

    2) Voice mail machines usually act as an integrated Message
    Transfer Agent, Message Store and User Agent.  There is typically
    no relaying of messages.  RFC822 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.
 It should be noted that newer systems are based natively on SMTP/MIME
 and do not suffer these limitations.  In particular, some systems may
 support media other than voice and fax.

1.2. 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 are
 outside the scope of this document.

Vaudreuil & Parsons Standards Track [Page 4] RFC 3801 VPIMv2 June 2004

 This profile is intended to be robust enough to be used in an
 environment, such as the global Internet, with installed-base
 gateways that do not understand MIME.  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 special configuration is required to receive VPIM
 conforming messages, some may be required to originate conforming
 structures.
 It is expected that a system administrator who can perform TCP/IP
 network configuration will manage a VPIM messaging system.  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.

1.3. Applicability for VPIM

 VPIM is intended for the exchange of voice messages between
 traditional voice messaging systems and for systems that need to
 interoperate with such systems.  VPIM is intended connect voice-
 messaging systems into special-purpose voice messaging networks.
 VPIM may also be used between message store servers and VPIM-aware
 clients such as web servers, TUI, and GUI clients.  VPIM is not
 intended or optimized for downloading to, or sending from commercial
 email clients.
 Internet Voice Messaging, the subject of a separate standards
 initiative, is intended to enable general-purpose email clients to
 send and receive voice content through general-purpose message stores
 in an interoperable way.  IVM may also be a suitable format for
 downloading voice messages from a VPIM server to a commercial email
 client.  It may also be a suitable format for submission of a voice
 message from a general-purpose client into a VPIM system.

2. Requirements Language

 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 3801 VPIMv2 June 2004

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 [SIZE]
 to declare the maximum message size supported.
 The following sections describe the restrictions and additions to
 Internet mail protocols that are required to be conforming 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.  The table in Appendix A summarizes the protocol
 details of this profile.

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 [MIME1-5], the
 X.400 gateway specification [X.400], and the delivery status and
 message disposition notifications [REPORT][DSN][DRPT][STATUS][MDN].
 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:" MIME 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".

Vaudreuil & Parsons Standards Track [Page 6] RFC 3801 VPIMv2 June 2004

4.1. VPIM Message Addressing Formats

 VPIM addresses SHALL use the RFC 822 format 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 SHALL be a printable string containing the mailbox ID
 of the originator or recipient.  While alpha characters and long
 mailbox identifiers MAY be permitted, short numeric local parts
 SHOULD be used as 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 unreplyable.  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 Name 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
 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

Vaudreuil & Parsons Standards Track [Page 7] RFC 3801 VPIMv2 June 2004

    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) +international number+extension
        - 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 to represent the sender 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
 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" SHOULD 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. A conforming implementation MUST NOT permit a reply to an

Vaudreuil & Parsons Standards Track [Page 8] RFC 3801 VPIMv2 June 2004

 address from "non-mail-user".  For compatibility with the installed
 base of mail user agents, implementations MUST reject the message
 when a message addressed to "non-mail-user" is received.  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'.  A VPIM implementation MAY support DLs.  Using a
 simple alias is a behavior closest to what many voice mail systems do
 today and what is to be used with VPIM messages.  A couple of
 important features that need special care when DLs are used are:
    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 or the "Return-Path:"
                               RFC822 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 then the recipient header fields
 SHOULD be omitted to indicate that an accurate list of recipients
 (e.g., for use with a reply-all capability) is not known.

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 messages:

Vaudreuil & Parsons Standards Track [Page 9] RFC 3801 VPIMv2 June 2004

4.2.1. From

 SEND RULES
 The originator's fully qualified domain address (a mailbox address
 followed by the fully qualified domain name) MUST be present.
 Systems conforming 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>
             From: Non-mail-user@myserver.mycompany.com
 Voice mail machines may not be able to support separate attributes
 for the "From:" header fields and the SMTP MAIL FROM, 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.
 RECEIVE RULES
 The user listed in the "From:" field MUST be presented in the voice
 message envelope of the voice messaging system as the originator of
 the message, though the exact presentation is an implementation
 decision (e.g., the mailbox ID or the text name MAY be presented).
 The "From:" address SHOULD be used for replies (see 4.9).

4.2.2. To

 The "To:" field contains the recipient's fully-qualified domain
 address.
 Example:
             To: +12145551213@mycompany.com
 SEND RULES
 There MAY be one or more "To:" fields in any message.  Systems SHOULD
 provide a list of recipients only if all recipients are available.

Vaudreuil & Parsons Standards Track [Page 10] RFC 3801 VPIMv2 June 2004

 Systems, such as gateways from protocols or legacy platforms that do
 not indicate the complete list of recipients, MAY provide a "To:"
 line. Because these systems cannot accurately enumerate all
 recipients in the "To:" headers, recipients SHOULD NOT be enumerated.
 RECEIVE RULES
 Systems conforming to this profile MAY discard the addresses in the
 "To:" fields if they are unable to store the information.  This
 would, of course, make a reply-to-all capability impossible.  If
 present, the addresses in the "To:" field MAY be used for a reply
 message to all recipients.

4.2.3. Cc

 The "Cc:" field 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 additional recipients.
 SEND RULES
 Conforming implementations MAY send "Cc:" lists if all recipients are
 known at the time of origination.  If not, systems SHOULD omit the
 "Cc:" fields to indicate that the full list of recipients is unknown
 or otherwise unavailable.  The list of disclosed recipients MUST NOT
 include undisclosed recipients (i.e., those sent via a blind copy).
 Example:
             Cc: +12145551213@mycompany.com
 RECEIVE RULES
 Systems conforming to this profile MAY add all the addresses in the
 "Cc:" field to the "To:" field, others MAY discard the addresses in
 the "Cc:" fields.  If a list of "Cc:" addresses is present, these
 addresses MAY be used for a reply message to all recipients.

4.2.4. Date

 The "Date:" field contains the date and time the message was sent by
 the originator.
 SEND RULES
 The sending system MUST report the time the message was sent.  The
 time zone MUST be present and SHOULD be represented in a four-digit

Vaudreuil & Parsons Standards Track [Page 11] RFC 3801 VPIMv2 June 2004

 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., "-0700 (PDT)".
 Example:
             Date: Wed, 28 Jul 96 10:08:49 -0800 (PST)
 If the VPIM sender is relaying a message from a system that does not
 provide a time stamp, the time of arrival at the gateway system
 SHOULD be used as the date.
 RECEIVE RULES
 Conforming implementations SHOULD be able to convert [RFC822] date
 and time stamps into local time

4.2.5. Sender

 The "Sender:" field contains the actual address of the originator if
 an agent on behalf of the author indicated in the "From:" field sends
 the message.
 SEND RULES
 This header field MAY be sent by VPIM-conforming systems.
 RECEIVE RULES
 If the address in the "Sender:" field cannot be preserved in the
 recipient's message queues or in the next-hop protocol from a
 gateway, the field MAY be silently discarded.

4.2.6. Return-Path

 The "Return-path:" field is added by the final delivering SMTP
 server. If present, it contains the address from the MAIL FROM
 parameter of the ESMTP exchange (see [RFC822]).  Any error messages
 resulting from the delivery failure MUST be sent to this address.
 Note that if the "Return-path:" is null ("<>") (e.g., a call answer
 message would have no return path) delivery status notifications MUST
 NOT be sent.
 SEND RULES
 The originating system MUST NOT add this header.

Vaudreuil & Parsons Standards Track [Page 12] RFC 3801 VPIMv2 June 2004

 RECEIVE RULES
 If the receiving system is incapable of storing the return path (or
 MAIL FROM) to be used for subsequent delivery errors (i.e., it is a
 gateway to a legacy system or protocol), the receiving system must
 otherwise ensure that further delivery errors don't happen.  Systems
 that do not support the return path MUST ensure that at the time the
 message is acknowledged (i.e., when a DSN would be sent), the message
 is delivered to the recipient's ultimate mailbox.  Non-Delivery
 notifications SHOULD NOT be sent after that final delivery.

4.2.7. Message-id

 The "Message-Id:" field contains a globally unique per-message
 identifier.
 SEND RULES
 A globally unique message-id MUST be generated for each message sent
 from a VPIM-conforming implementation.
 Example:
             Message-Id: <12345678@mycompany.com>
 RECEIVE RULES
 When provided in the original message, it MUST be used when sending a
 MDN.  This identifier MAY be used for tracking and auditing.  From
 [RFC822]

4.2.8. Reply-To

 If present, the "Reply-To:" header provides a preferred address to
 which reply messages should be sent (see 4.9).  Typically, voice mail
 systems can only support one originator of a message so it is likely
 that this field will be ignored by the receiving system.  From:
 [RFC822]
 SEND RULES
 A conforming system SHOULD NOT send a "Reply-To:" header.
 RECEIVE RULES
 If a "Reply-To:" field is present, a reply-to-sender message MAY be
 sent to the address specified (that is, in lieu of the address in the
 "From:" field).  If the receiving system (e.g., multi-protocol

Vaudreuil & Parsons Standards Track [Page 13] RFC 3801 VPIMv2 June 2004

 gateway) only supports one address for the originator, then the
 address in the "From:" field MUST be used and the "Reply-To:" field
 MAY be silently discarded.

4.2.9. Received

 The "Received:" field contains trace information added to the
 beginning of a RFC822 message by MTAs.  This is the only field that
 may 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.  From: [RFC822]
 SEND RULES
 A VPIM-conforming system MUST add a "Received:" field.  When acting
 as a gateway, information about the system from which the message was
 received SHOULD be included.
 RECEIVE RULES
 A VPIM-conforming system 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.

4.2.10. MIME Version

 The "MIME-Version:" field MUST be present to indicate that the
 message conforms to [MIME1-5].  Systems conforming with this
 specification SHOULD include a comment with the words "(Voice 2.0)".
 [VPIM1] defines an earlier version of this profile and uses the token
 (Voice 1.0). 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 multipart/voice-message content type
 defined in section 18.2 SHOULD be used if identification is
 necessary.

4.2.11. Content-Type

 The "Content-Type:" header MUST be present to declare the type of
 content enclosed in the message.  The typical top-level content in a
 VPIM Message SHOULD be Multipart/Voice-Message.  The allowable
 contents are detailed starting in section 4.4 of this document.
 From: [MIME2]

Vaudreuil & Parsons Standards Track [Page 14] RFC 3801 VPIMv2 June 2004

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.
 SEND RULES
 An implementation in conformance with this profile SHOULD send audio
 and/or facsimile data in "Binary" form when binary message transport
 is available (see section 5).  When binary transport is not
 available, implementations MUST encode the audio and/or facsimile
 data as "Base64".
 RECEIVE RULES
 Conforming implementations MUST recognize and decode the standard
 encodings, "Binary" (when binary support is available), "7bit,
 "8bit", "Base64" and "Quoted-Printable" per [MIME1].  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.

4.2.13. Sensitivity

 The "Sensitivity:" field, if present, indicates the requested privacy
 level.  If no privacy is requested, this field is omitted.  The
 header definition is as follows:
 Sensitivity := "Sensitivity" ":" Sensitivity-value
 Sensitivity-value := "Personal" / "Private" / "Company-Confidential"
 SEND RULES
 A VPIM-conforming implementation MAY include this header to indicate
 the sensitivity of a message.  If a user marks a message "Private", a
 conforming implementation MUST send only the "Private" sensitivity
 level.  There are no VPIM-specific semantics defined for the values
 "Personal" or "Company-Confidential".  A conforming implementation
 SHOULD NOT send the values "Personal" or "Company-Confidential".  If
 the message is of "Normal" sensitivity, this field SHOULD be omitted.
 From: [X.400]

Vaudreuil & Parsons Standards Track [Page 15] RFC 3801 VPIMv2 June 2004

 RECEIVE RULES
 If a "Sensitivity:" field with a value of "Private" is present in the
 message, a conforming system MUST prohibit the recipient from
 forwarding this message to any other user.  A conforming system,
 however, SHOULD allow the responder to reply to a sensitive message,
 but SHOULD NOT include the original message content.  The responder
 MAY set the sensitivity of the reply message.
 A receiving system MAY ignore sensitivity values of "Personal" and
 "Company Confidential".
 If the receiving system does not support privacy and the sensitivity
 is "Private", a negative delivery status notification MUST be sent to
 the originator with the appropriate status code (5.6.0) "Other or
 undefined protocol status" 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]
 A message with no privacy explicitly noted (i.e., no header) or with
 "Normal" sensitivity has no special treatment.

4.2.14. Importance

 Indicates the requested importance to be given by the receiving
 system. If no special importance is requested, this header MAY be
 omitted and the value of the absent header assumed to be "normal".
 From: [X.400]
 Importance := "Importance" ":" importance-value
 Importance-value := "low" / "normal" / "high"
 SEND RULES
 Conforming implementations MAY include this header to indicate the
 importance of a message.
 RECEIVE RULES
 If the receiving system does not support "Importance:", the attribute
 MAY be silently dropped.

Vaudreuil & Parsons Standards Track [Page 16] RFC 3801 VPIMv2 June 2004

4.2.15. Subject

 The "Subject:" field is often provided by email systems but is not
 widely supported on voice mail platforms.  From: [RFC822]
 SEND RULES
 For compatibility with text-based mailbox interfaces, a text subject
 field SHOULD be generated by a conforming implementation.  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" or "Voice Message" for the benefit
 of GUI-enabled recipients.
 RECEIVE RULES
 It is anticipated that many voice-only systems will be incapable of
 storing the subject line.  The subject MAY be discarded by a
 receiving system.

4.3. MIME Audio Content Descriptions

4.3.1. 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.
 Example:
       Content-Description: Big Telco Voice Message
 SEND RULES
 This field MAY be added to a voice body part to offer a freeform
 description of the voice content.  It is useful to incorporate the
 values for Content-Disposition with additional descriptions.  For
 example, this can be used to indicate product name or transcoding
 records.
 RECEIVE RULES
 This field MAY be displayed to the recipient.  However, since it is
 only informative it MAY be ignored.

Vaudreuil & Parsons Standards Track [Page 17] RFC 3801 VPIMv2 June 2004

4.3.2. Content-Disposition

 This field MUST be present to allow the parsable identification of
 body parts within a VPIM voice message.  This is especially useful
 if, as is typical, more than one Audio/* body occurs within a single
 level (e.g., Multipart/Voice-Message).  Since a VPIM voice message is
 intended to be automatically played in the order in which the audio
 contents occur, the audio contents MUST always be of disposition
 inline.  However, it is still useful to include a filename value, so
 this SHOULD be present if this information is available.  From:
 [DISP]
 SEND RULES
 In order to distinguish between the various types of audio contents
 in a VPIM voice message a new disposition parameter "voice" is
 defined with IANA (see section 18.1) with the parameter values below
 to be used as appropriate:
 Audio-Type := "voice" "=" Audio-type-value
 Audio-type-value := "Voice-Message" / "Voice-Message-Notification" /
 "Originator-Spoken-Name" /"Recipient-Spoken-Name" /"Spoken-Subject"
    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(s) if
      available to the originator
    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
 or reply voice message.  If there are multiple recipients for a given
 message, recipient-spoken-name MUST NOT be used.
 RECEIVE RULES
 Implementations SHOULD use this header.  However, those that do not
 understand the "voice" parameter (or the "Content-Disposition:"
 header) can safely ignore it, and will present the audio body parts
 in order (but will not be able to distinguish between them).  If more
 than one instance of the "voice" parameter type value is encountered
 at one level (e.g., multiple 'Voice-Message' tagged contents) then
 they SHOULD be presented together.

Vaudreuil & Parsons Standards Track [Page 18] RFC 3801 VPIMv2 June 2004

4.3.3. Content-Duration

 The "Content-Duration:" header provides an indication of the audio
 length in seconds of the segment.
 Example:
       Content-Duration: 33
 SEND RULES
 This field MAY be present to allow the specification of the length of
 the audio body part in seconds.
 RECEIVE RULES
 The use of this field on reception is a local implementation issue.
 From: [DUR]

4.3.4. Content-Language:

 This field MAY be present to allow the specification of the spoken
 language of the audio body part.  The encoding is defined in [LANG].
 Example for UK English:
       Content-Language: en-UK
 SEND RULES
 A sending system MAY add this field to indicate the language of the
 voice.  The determination of this (e.g., automated or user-selected)
 is a local implementation issue.
 RECEIVE RULES
 The use of this field on reception is a local implementation issue.
 It MAY be used as a hint to the recipient (e.g., end-user or an
 automated translation process) as to the language of the voice
 message.

4.4. Voice Message Content Types

 The content types described in this section are identified for use
 within the Multipart/Voice-Message content.  This content is referred
 to as a "VPIM message" in this document and is the fundamental part
 of a "VPIM message".

Vaudreuil & Parsons Standards Track [Page 19] RFC 3801 VPIMv2 June 2004

 Only the contents profiled can be sent within a VPIM voice message
 construct (i.e., the Multipart/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 not permitted. In the absence of a bilateral agreement,
 conforming implementations MUST NOT create a message containing
 prohibited contents.  In the spirit of liberal acceptance, a
 conforming implementation MAY accept and render prohibited content.
 Systems unable to accept or render prohibited contents MAY discard
 the prohibited contents as necessary to deliver the acceptable
 content.  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.
 Some deployed implementations based on a common interpretation of the
 original VPIM v2 specification reject messages with prohibited
 content rather than discard the unsupported contents.  For
 interoperability with these systems, it is especially important that
 prohibited contents not be sent within a Multipart/Voice-Message.

4.4.1. Multipart/Voice-Message

 This MIME multipart structure provides a mechanism for packaging a
 voice message into one container that is tagged as VPIM v2
 conforming.  The sub-type is identical in semantics and syntax to
 multipart/mixed, as defined in [MIME2].  As such, it may be safely
 interpreted as a multipart/mixed by systems that do not understand
 the sub-type (only the identification as a voice message would be
 lost).
 In addition to the MIME required boundary parameter, a version
 parameter is also required for this sub-type.  This is to distinguish
 this refinement of the sub-type from the previous definition in
 [VPIM1].  The value of the version parameter is "2.0" if the content
 conforms to the requirements of this specification.  Should there be
 further revisions of this content type, there MUST be backwards
 compatibility (i.e., systems implementing version n can read version
 2, and systems implementing version 2 can read version 2 contents
 within a version n).
 SEND RULES
 The Multipart/Voice-Message content-type MUST only contain the
 profiled media and content types specified in this section (i.e.,
 Audio/*, Image/*, and Message/RFC822).  The most common will be:
 spoken name, spoken subject, the message itself, and an attached fax.
 Forwarded messages are created by simply using the Message/RFC822
 construct.

Vaudreuil & Parsons Standards Track [Page 20] RFC 3801 VPIMv2 June 2004

 Conformant implementations MUST use Multipart/Voice-Message in a VPIM
 message.  In most cases, this Multipart/Voice-Message Content-Type
 will be the top level but may be included within a Message/RFC822 if
 the message is forwarded or within a multipart/mixed when more than
 one message is being forwarded.
 RECEIVE RULES
 Conformant implementations MUST recognize the Multipart/Voice-Message
 content (whether it is a top-level content or contained in a
 Multipart/Mixed) and MUST be able to separate the contents (e.g.,
 spoken name or spoken subject).
 The semantic of Multipart/Voice-Message (defined in section 18.2) is
 identical to Multipart/Mixed and may be interpreted as that by
 systems that do not recognize this content-type.

4.4.2. Message/RFC822

 SEND RULES
 MIME requires support of the Message/RFC822 message encapsulation
 body part.  This body part SHOULD be used within a Multipart/Voice-
 Message to forward complete messages (see 4.8) or to reply with
 original content (see 4.9).  From: [MIME2]
 RECEIVE RULES
 The receiving system MUST accept this format and SHOULD treat this
 attachment as a forwarded message.  The receiving system MAY flatten
 the forwarding structure (i.e., remove this construct to leave
 multiple voice contents or even concatenate the voice contents to fit
 in a recipient's mailbox), if necessary.

4.4.3. Audio/32KADPCM

 SEND RULES
 An implementation conforming to this profile MUST send Audio/32KADPCM
 by default for voice [ADPCM].  This encoding is a moderately-
 compressed encoding with a data rate of 32 kbits/second using
 moderate processing resources. Typically, this body contains several
 minutes of message content;  however, if used for spoken name or
 subject the content is expected to be considerably shorter (i.e.,
 about 5 and 10 seconds respectively).

Vaudreuil & Parsons Standards Track [Page 21] RFC 3801 VPIMv2 June 2004

 RECEIVE RULES
 Receivers MUST be able to accept and decode Audio/32KADPCM.  If an
 implementation can only handle one voice body, then multiple voice
 bodies (if present) SHOULD be concatenated, and MUST NOT be
 discarded. If concatenated, the contents SHOULD be in the same order
 they appeared in the multipart.

4.4.4. 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 within
 Multipart/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.
 SEND RULES
 All VPIM implementations that support facsimile MUST generate TIFF-F
 compatible facsimile contents in the Image/TIFF subtype using the
 application=faxbw encoding by default.  If the VPIM message is a
 voice- annotated fax, the implementation SHOULD send this fax content
 in Multipart/Voice-Message.  If the message is a simple fax, an
 implementation MAY send it without using the Multipart/Voice-Message
 to be more compatible with fax-only (RFC 2305) implementations.
 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.
 RECEIVE RULES
 Not all VPIM systems support fax, but all SHOULD accept it within the
 multipart/voice-message.  Within a Multipart/Voice-Message, a
 receiving system that cannot render fax content SHOULD accept the
 voice content of a VPIM message and discard the fax content.  Outside
 a Multipart/Voice-Message, a recipient system MAY reject (with
 appropriate NDN) the entire message if it cannot store or is not
 capable of rendering a message with fax attachments.  VPIM conforming
 systems MAY support fax outside of (or without) the Multipart/Voice-
 Message.

Vaudreuil & Parsons Standards Track [Page 22] RFC 3801 VPIMv2 June 2004

 Some deployed implementations based on a common interpretation of the
 original VPIM V2 specification reject messages with fax content
 within the Multipart/Voice-Message rather than discard the
 unsupported contents. These systems will return the message to the
 sender with an NDN indicating lack of support for fax.

4.5. Other MIME Contents

 The following MIME contents (with the exception of multipart/mixed in
 section 4.5.1) MAY be included within a multipart/voice message.
 Other contents MUST NOT be included.  Their handling is a local
 implementation issue.  Multipart/mixed is included to promote
 interoperability with a wider range of systems and also to allow the
 creation of more complex multimedia messages (with a VPIM message as
 one part).

4.5.1. Multipart/Mixed

 This common MIME content-type allows the enclosing of several body
 parts in a single message.
 SEND RULES
 A VPIM voice message (i.e., multipart/voice-message) MAY be included
 within a message with a Multipart/Mixed top-level content type.
 Typically, this would only be used when mixing non-voice and non-fax
 contents with a voice message.
 RECEIVE RULES
 Such a message is not itself a VPIM message and the handling of such
 a construct is outside the scope of the VPIM profile.  However, an
 the spirit of liberal acceptance, a conforming implementation MUST
 accept and render a VPIM voice message contained in a
 Multipart/Mixed.

4.5.2. Text/Directory

 SEND RULES
 This content was profiled in the original specification of VPIM v2 as
 a means of transporting contact information from the sender to the
 recipient.  This usage did not find widespread adoption and is no
 longer a feature of VPIM V2.  Conforming implementations SHOULD NOT
 send the Text/Directory content type.

Vaudreuil & Parsons Standards Track [Page 23] RFC 3801 VPIMv2 June 2004

 RECEIVE RULES
 For compatibility with an earlier specification of VPIM v2, the
 Text/Directory content type MUST be accepted by a conforming
 implementation, but need not be stored, processed, or rendered to the
 recipient.

4.5.3. Proprietary Voice or Fax Formats

 Use of any other encoding except the required codecs reduces
 interoperability in the absence of explicit knowledge about the
 capabilities of the recipient.  A conforming implementation SHOULD
 NOT use any other encoding unless a unique identifier is registered
 with the IANA prior to use (see [MIME4]).  The voice encodings SHOULD
 be registered as subtypes of Audio. The fax encodings SHOULD be
 registered as subtypes of Image.
 SEND RULES
 Proprietary voice encoding formats or other standard formats SHOULD
 NOT be sent under this profile unless the sender has a reasonable
 expectation that the recipient will accept the encoding.  In
 practice, this requires explicit per-destination configuration
 information maintained either in a directory, personal address book,
 or gateway configuration tables.
 RECEIVE RULES
 Systems MAY accept other Audio/* or Image/* content types if they can
 decode them.  Systems which receive Audio/* or Image/* content types
 which they are unable to deposit or unable to render MUST return the
 message (and SHOULD include the original content) to the originator
 with an NDN indicating media not supported.

4.5.4. Text/Plain

 MIME requires support of the basic Text/Plain content type (with the
 US-ASCII character set).  This content type has limited applicability
 within the voice-messaging environment.  However, because VPIM is a
 MIME profile, MIME requirements SHOULD be met.
 SEND RULES
 Conforming VPIM implementations SHOULD NOT send the Text/Plain
 content-type.  Implementations MAY send the Text/Plain content-type
 outside the Multipart/Voice-Message.

Vaudreuil & Parsons Standards Track [Page 24] RFC 3801 VPIMv2 June 2004

 RECEIVE RULES
 Within a Multipart/Voice-Message, the Text/Plain content-type MAY be
 dropped from the message, if necessary, to deliver the audio/fax
 components.  The recipient SHOULD NOT reject the entire message if
 the text component cannot be accepted or rendered.
 Outside a Multipart/Voice-Message, conforming implementations MUST
 accept Text/Plain; however, specific handling is left as an
 implementation decision.  From: [MIME2]
 Some deployed implementations based on a common interpretation of the
 original VPIM V2 specification reject messages with any text content
 rather than discard the unsupported contents.  These systems will
 return the message to the sender with an NDN indicating lack of
 support for text.

4.6. Delivery Status Notification (DSN)

 A DSN is a notification of delivery (positive DSN), non-delivery
 (negative DSN), or temporary delivery delay (delayed DSN).  The top-
 level content-type of a DSN is Multipart/Report, which is defined in
 [REPORT].  The content-type which distinguishes DSN's from other
 types of notifications is Message/Delivery-Status, which is defined
 in [DSN].
 SEND RULES
 A VPIM-compliant implementation MUST be able to send DSN's that
 conform to [REPORT] and [DSN].  Unless requested otherwise, a non-
 delivery DSN MUST be sent when any form of non-delivery of a message
 occurs.
 A VPIM-compliant implementation SHOULD provide a spoken delivery
 status in the "human-readable" body part of the DSN, but MAY provide
 a textual status.
 RECEIVE RULES
 A VPIM-compliant implementation MUST be able to receive DSN's that
 conform to [REPORT] and [DSN].
 A VPIM-compliant implementation MUST be able to receive a DSN whose
 "human-readable" body part contains a spoken delivery status phrase
 or a textual description.  Though subsequent use of the phrase or
 text is a local implementation issue, the intent of the DSN MUST be
 presented to the end user.

Vaudreuil & Parsons Standards Track [Page 25] RFC 3801 VPIMv2 June 2004

4.7. Message Disposition Notification (MDN)

 An MDN is a notification indicating what happens to a message after
 it is deposited in the recipient's mailbox.  An MDN can be positive
 (message was read/played/rendered/etc.) or negative (message was
 deleted before recipient could see it, etc.).  The top-level
 content-type of a MDN is Multipart/Report, which is defined in
 [REPORT].  The content-type which distinguishes MDN's from other
 types of notifications is Message/Disposition-Notification, which is
 defined in [MDN].
 SEND RULES
 A VPIM-compliant implementation SHOULD support the ability to request
 MDNs.  This is done via the use of the "Disposition-Notification-To:"
 header field as defined in [MDN].
 A VPIM-compliant implementation SHOULD support the ability to send
 MDNs, but these MDNs MUST conform to [REPORT] and [MDN].
 When sending an MDN, a VPIM-compliant implementation SHOULD provide a
 spoken message disposition in the "human-readable" body part of the
 MDN, but MAY provide a textual status.
 RECEIVE RULES
 A VPIM-compliant implementation SHOULD respond to an MDN request with
 an MDN response.
 A VPIM-compliant implementation MUST be able to receive MDNs that
 conform to [REPORT] and [MDN], if it is capable of requesting MDNs.
 If a VPIM-compliant implementation is capable of receiving MDNs, it
 MUST be able to receive a MDN whose "human-readable" body part
 contains a spoken message disposition phrase or a textual disposition
 description.  Though subsequent use of the phrase or text is a local
 implementation issue, the intent of the MDN MUST be presented to the
 end user.

4.8. Forwarded Messages

 VPIM v2 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.

Vaudreuil & Parsons Standards Track [Page 26] RFC 3801 VPIMv2 June 2004

 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:" field.  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, the entire audio
 content MAY be sent as a single Audio/* segment without including any
 forwarding semantics.  An example of this loss is an AMIS message
 being forwarded through an AMIS-to-VPIM gateway.

4.9. Reply Messages

 VPIM v2 explicitly supports replying to received messages.
 Support of multiple originator header fields in a reply message 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 DSN's, MDN's, and replies to their proper
 destinations.
 In some cases, replying to a message is not possible, such as with a
 message created by telephone answering (i.e., classic voice mail).
 In this case, the From field SHOULD contain the special address non-
 mail-user@domain (see 4.1.2).  The recipient's VPIM system SHOULD NOT
 offer the option to reply to this kind of message (unless an
 outcalling feature is offered - which is out of scope for VPIM).

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
 "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

Vaudreuil & Parsons Standards Track [Page 27] RFC 3801 VPIMv2 June 2004

 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. Base SMTP Protocol

 A conforming system MUST implement all mandatory SMTP and ESMTP
 commands.  Any defined optional command or parameter MAY be
 supported.

5.2. SMTP Service Extensions

 VPIM utilizes a number of SMTP Service Extensions to provide full-
 featured voice messaging service.  The following extensions are
 profiled for use with VPIM:

5.2.1. DSN Extension

 The DSN extension defines a mechanism which allows an SMTP client to
 specify (a) DSN's should be generated under certain conditions, (b)
 whether such DSN's should return the contents of the message, and (c)
 additional information, to be returned with a DSN, that allows the
 sender to identify both the recipient(s) for which the DSN was
 issued, and the transaction in which the original message was sent.
 The DSN extension MUST be supported by VPIM conforming
 implementations.
 In addition, beyond the requirements of [DRPT], conforming
 implementations MUST support NOTIFY parameter on the RCPT command to
 allow indication of when the originator requests a notification.  The
 RET parameter SHOULD be supported to return the original message with
 the notification.  Parameters ORCPT and ENVID MAY also be supported.
 From: [DRPT]

5.2.2. SIZE Extension

 The SIZE extension defines a mechanism whereby an SMTP client and
 server may interact to give the server an opportunity to decline to
 accept a message (perhaps temporarily) based on the client's estimate
 of the message size.  From: [SIZE]

Vaudreuil & Parsons Standards Track [Page 28] RFC 3801 VPIMv2 June 2004

 The SIZE extension MUST be supported by VPIM-compliant
 implementations.

5.2.3. ENHANCEDSTATUSCODES Extension

 The ENHANCEDSTATUSCODES extension defines a mechanism whereby an SMTP
 server augments its responses with the enhanced mail system status
 codes defined in [CODES].  These codes can then be used to provide
 more informative explanations of error conditions.  From: [STATUS]
 The ENHANCEDSTATUSCODES extension SHOULD be supported by VPIM-
 compliant implementations.

5.2.4. PIPELINING Extension

 The PIPELINING extension defines a mechanism whereby an SMTP server
 can indicate the extent of its ability to accept multiple commands in
 a single TCP send operation.  Using a single TCP send operation for
 multiple commands can improve SMTP performance significantly.  From
 [PIPE]
 The PIPELINING extension SHOULD be supported by VPIM-compliant
 implementations.

5.2.5. CHUNKING Extension

 The CHUNKING extension defines a mechanism that enables an SMTP
 client and server to negotiate the use of the message data transfer
 command "BDAT" (in alternative to the DATA command) for efficiently
 sending large MIME messages.  From: [BINARY]
 The CHUNKING extension MAY be supported by VPIM-compliant
 implementations.

5.2.6. BINARYMIME Extension

 The BINARYMIME extension defines a mechanism that enables an SMTP
 client and server to negotiate the transfer of unencoded binary
 message data utilizing the BDAT command.  From: [BINARY]
 The BINARYMIME extension MAY be supported by VPIM-compliant
 implementations.  Note that [BINARY] specifies that if BINARYMIME is
 to be supported, then CHUNKING has to be supported by definition.

Vaudreuil & Parsons Standards Track [Page 29] RFC 3801 VPIMv2 June 2004

5.3. ESMTP - SMTP Downgrading

 The SMTP extensions suggested or required for conformance to VPIM
 fall into two categories.  The first category includes features that
 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 is 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-conforming ESMTP support the 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 delivery status
 notification.  It is RECOMMENDED that the downgrading system should
 continue to attempt to deliver the message, but MUST send an
 appropriate delivery status notification to the originator, e.g., the
 message left an ESMTP host and was sent relayed to a non-DSN-aware
 destination, and this may be the last DSN received.

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 offer only a
 telephone user interface.  The mapping of the dialed target number to
 a routable FQDN address, allowing delivery to the destination system,
 can be accomplished through implementation-specific means.
 To facilitate a local cache, an implementation may wish to populate
 local directories with the first and last names, as well as the
 senders' spoken name information extracted from received messages.
 Addresses or names parsed from the header fields of VPIM messages MAY
 be used to populate directories.

7. 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 VPIM-conforming machine.

Vaudreuil & Parsons Standards Track [Page 30] RFC 3801 VPIMv2 June 2004

7.1. 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].

8. Conformance Requirements

 VPIM is a messaging application that will 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-
 conformant.
 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 conformance requirements is contained in Appendix A.
 VPIM end systems are expected to be both transport- and content-
 conformant.  Voice messaging systems and protocol conversion gateways
 are considered end systems.
 Relay systems are expected to be transport-conformant in order to
 receive and send conforming messages.  However, they must also create
 VPIM-conforming delivery status notifications in the event of
 delivery problems.
 Desktop Email clients that support VPIM 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

Vaudreuil & Parsons Standards Track [Page 31] RFC 3801 VPIMv2 June 2004

 transport capabilities, specific client-server requirements are out-
 of-scope for this document.

9. Security Considerations

9.1. 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 Internet security infrastructure,
 rather than a new mechanism or some other mechanism outside of the
 Internet infrastructure.

9.2. 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 that ensue from integrating the two
 services.

9.2.1. Spoofed sender

 The actual sender of the voice message might not be the same as that
 specified in the "Sender:" or "From:" message 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 sender's 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.

9.2.2. 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
 curb this problem.

Vaudreuil & Parsons Standards Track [Page 32] RFC 3801 VPIMv2 June 2004

9.2.3. Message disclosure

 Users of voice messaging systems have an expectation of a level of
 message privacy that 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.

9.3. 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.

10. Normative References

 [8BIT]    Klensin, J., Freed, N., Rose, M., Stefferud, E. and D.
           Crocker, "SMTP Service Extension for 8bit-MIMEtransport",
           RFC 1652, July 1994.
 [ADPCM]   Vaudreuil, G. and G. Parsons, "Toll Quality Voice - 32
           kbit/s Adaptive Differential Pulse Code Modulation (ADPCM)
           MIME Sub-type Registration", RFC 3802, June 2004.
 [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 3030, December 2000.
 [CODES]   Vaudreuil, G. "Enhanced Mail System Status Codes", RFC
           1893, January 1996.
 [MIMEDIR] Dawson, F., Howes, T. and M. Smith, "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", RFC 1035, November 1987.

Vaudreuil & Parsons Standards Track [Page 33] RFC 3801 VPIMv2 June 2004

 [DNS2]    Mockapetris, P., "Domain names - concepts and facilities",
           RFC 1034, November 1987.
 [DRPT]    Moore, K., "Simple Mail Transfer Protocol (SMTP) Service
           Extension for Delivery Status Notifications (DSNs)", RFC
           3461, January 2003.
 [DSN]     Moore, K. and G. Vaudreuil, "An Extensible Message Format
           for Delivery Status Notifications", RFC 3464, January 2003.
 [DUR]     Parsons, G. and G. Vaudreuil, "Content Duration MIME Header
           Definition", RFC 3803, June 2004.
 [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., "Simple Mail Transfer Protocol", RFC 2821,
           April 2001.
 [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",
           BCP 47, RFC 3066, January 2001.
 [MDN]     Hansen, T., Ed. and G. Vaudreuil, Ed., "Message Disposition
           Notification", RFC 3798, May 2004.
 [MIB II]  Rose, M., "Management Information Base for Network
           Management of TCP/IP-based internets:  MIB-II", RFC 1213,
           March 1991.
 [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.

Vaudreuil & Parsons Standards Track [Page 34] RFC 3801 VPIMv2 June 2004

 [MIME3]   Moore, K., "Multipurpose Internet Mail Extensions (MIME)
           Part Three: Message Header Extensions for Non-ASCII Text ",
           RFC 2047, November 1996.
 [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" STD 60, RFC 2920, September 2000.
 [REPORT]  Vaudreuil, G., "The Multipart/Report Content Type for the
           Reporting of Mail System Administrative Messages", RFC
           3462, January 2003.
 [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" STD 10, RFC 1870,
           November 1995.
 [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 registration", 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.

Vaudreuil & Parsons Standards Track [Page 35] RFC 3801 VPIMv2 June 2004

 [VPIM2]   Vaudreuil, G. and G. Parsons, "Voice Profile for Internet
           Mail, Version 2", RFC 2421, September 1998.
 [X.400]   CCITT/ISO, "CCITT Recommendations X.400/ ISO/IEC 10021-1,
           Message Handling: System and Service Overview", December
           1988.

11. 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 IETF VPIM Work Group, for their support
 of the VPIM specification and the efforts they have made to ensure
 its success.

Vaudreuil & Parsons Standards Track [Page 36] RFC 3801 VPIMv2 June 2004

12. 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 3801 VPIMv2 June 2004

                         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| | | |
   Numbers in mailbox IDs follow E.164      |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:                     |          | | | | | | |
   Sending outbound messages                |          | | | | | | |
     From                                   |4.2.1     |C|x| | | | |
       Addition of text name                |4.2.1     |C| |x| | | |
       Same value as MAIL FROM              |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            |4.7       |C| |x| | | |
     Other Headers                          |4.2       |C| | |x| | |
                                            |          | | | | | | |

Vaudreuil & Parsons Standards Track [Page 38] RFC 3801 VPIMv2 June 2004

                                            |          | | | | |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
 -------------------------------------------|----------|-|-|-|-|-|-|-
   Receiving 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| | |
       MDN requested                        |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            |4.7       |C| |x| | | |
     Other Headers                          |4.2       |C|x| | | | |3
                                            |          | | | | | | |
 Message Content Encoding:                  |          | | | | | | |
   Sending outbound audio/fax contents      |          | | | | | | |
     7BIT                                   |4.2.12    |C| | | | |x|
     8BIT                                   |4.2.12    |C| | | | |x|
     Quoted Printable                       |4.2.12    |C| | | | |x|
     Base64                                 |4.2.12    |C|x| | | | |4
     Binary                                 |4.2.12    |C| |x| | | |5
   Receiving inbound message contents       |          | | | | | | |
     7BIT                                   |4.2.12    |C|x| | | | |
     8BIT                                   |4.2.12    |C|x| | | | |
     Quoted Printable                       |4.2.12    |C|x| | | | |
     Base64                                 |4.2.12    |C|x| | | | |
     Binary                                 |4.2.12    |C|x| | | | |5
                                            |          | | | | | | |

Vaudreuil & Parsons Standards Track [Page 39] RFC 3801 VPIMv2 June 2004

                                                       | | | | |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:                     |          | | | | | | |
   Sending outbound messages                |          | | | | | | |
     Multipart/Voice-Message                |4.4.1     |C|x| | | | |
       Message/RFC822                       |4.4.2     |C| |x| | | |
       Audio/32KADPCM                       |4.4.3     |C|x| | | | |
         Content-Description                |4.3.1     |C| | |x| | |
         Content-Disposition                |4.3.2     |C|x| | | | |
         Content-Duration                   |4.3.3     |C| | |x| | |
         Content-Language                   |4.3.4     |C| | |x| | |
       Image/TIFF; application=faxbw        |4.4.4     |C|x| | | | |7
       Text/Directory                       |4.5.2     |C| | | |x| |9
       Text/plain                           |4.5.4     |C| | | |x| |
       Audio/* or Image/* (other encodings) |4.5.3     |C| | | |x| |
       Other contents                       |4.5       |C| | | | |x|
     Multipart/Mixed                        |4.5.1     |C| | |x| | |
     Text/plain                             |4.5.4     |C| | |x| | |
     Multipart/Report                       |4.6, 4.7  |C|x| | | | |
        human-readable part is voice        |4.6, 4.7  |C| |x| | | |
        human-readable part is text         |4.6, 4.7  |C| | |x| | |
        Message/Delivery-Status             |4.6       |C|x| | | | |
        Message/Disposition-Notification    |4.7       |C| |x| | | |
     Other contents                         |4.5       |C| | | |x| |6
   Receiving in inbound messages            |          | | | | | | |
     Multipart/Voice-Message                |4.4.1     |C|x| | | | |
       Message/RFC822                       |4.4.2     |C|x| | | | |
       Audio/32KADPCM                       |4.4.3     |C|x| | | | |
         Content-Description                |4.3.1     |C| | |x| | |
         Content-Disposition                |4.3.2     |C| |x| | | |
         Content-Duration                   |4.3.3     |C| | |x| | |
         Content-Language                   |4.3.4     |C| | |x| | |
       Image/TIFF; application=faxbw        |4.4.4     |C| |x| | | |8
       Text/Directory                       |4.5.2     |C|x| | | | |9
       Text/plain                           |4.5.4     |C| | |x| | |
       Audio/* or Image/* (other encodings) |4.5.3     |C| | |x| | |
       Other contents                       |4.5       |C| | |x| | |
     Multipart/Mixed                        |4.5.1     |C| | |x| | |

Vaudreuil & Parsons Standards Track [Page 40] RFC 3801 VPIMv2 June 2004

                                           |           | | | | |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
 ------------------------------------------|-----------|-|-|-|-|-|-|-
                                           |           | | | | | | |
    Text/plain                             |4.5.4      |C|x| | | | |
    Multipart/Report                       |4.6, 4.7   |C|x| | | | |
      human-readable part is voice         |4.6, 4.7   |C|x| | | | |
      human-readable part is text          |4.6, 4.7   |C|x| | | | |
      Message/Delivery-Status              |4.6        |C|x| | | | |
      Message/Disposition-Notification     |4.7        |C| |x| | | |
    Other contents                         |4.5        |C| | |x| | |6
                                           |           | | | | | | |
   Forwarded Messages                      |           | | | | | | |
     use Message/RFC822 construct          |4.8        |C| |x| | | |
     simulate headers if none available    |4.8        |C| |x| | | |
                                           |           | | | | | | |
   Reply Messages                          |4.9        |C|x| | | | |
     send to Reply-To, else From address   |4.2.8      |C| | |x| | |
     send to non-mail-user                 |4.9        |C| | | |x| |
                                           |           | | | | | | |
   Notifications                           |           | | | | | | |
     use Multipart/Report format           |4.6, 4.7   |C|x| | | | |
     always send error on non-delivery     |4.6        |C|x| | | | |
     send error messages to return-path    |4.2.6      |C|x| | | | |
                                           |           | | | | | | |
 Message Transport Protocol:               |           | | | | | | |
   Base ESMTP Commands                     |           | | | | | | |
     HELO                                  |5.1        |T|x| | | | |
     MAIL FROM                             |5.1        |T|x| | | | |
     RCPT TO                               |5.1        |T|x| | | | |
     DATA                                  |5.1        |T|x| | | | |
     TURN                                  |5.1        |T| | | | |x|
     QUIT                                  |5.1        |T|x| | | | |
     RSET                                  |5.1        |T|x| | | | |
     VRFY                                  |5.1        |T| | |x| | |
     EHLO                                  |5.1        |T|x| | | | |
     BDAT                                  |5.1        |T| | |x| | |5

Vaudreuil & Parsons Standards Track [Page 41] RFC 3801 VPIMv2 June 2004

                                                       | | | | |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              |          | | | | | | |
     DSN                                    |5.2.1     |T|x| | | | |
       NOTIFY                               |5.2.1     |T|x| | | | |
       RET                                  |5.2.1     |T| |x| | | |
       ENVID                                |5.2.1     |T| | |x| | |
       ORCPT                                |5.2.1     |T| | |x| | |
     SIZE                                   |5.2.2     |T|x| | | | |
     ENHANCEDSTATUSCODES                    |5.2.3     |T| |x| | | |
     PIPELINING                             |5.2.4     |T| |x| | | |
     CHUNKING                               |5.2.5     |T| | |x| | |
     BINARYMIME                             |5.2.6     |T| | |x| | |
                                            |          | | | | | | |
   ESMTP-SMTP Downgrading                   |          | | | | | | |
     send delivery report upon downgrade    |5.3       |T|x| | | | |
                                            |          | | | | | | |
 Directory Address Resolution               |          | | | | | | |
   provide facility to resolve addresses    |6         |C| |x| | | |
   use headers to populate local directory  |6         |C| | |x| | |
                                            |          | | | | | | |
 Management Protocols:                      |          | | | | | | |
   Network management                       |7.1       |T| | |x| | |
 -------------------------------------------|----------|-|-|-|-|-|-|-
 Footnotes:
 1.  SHOULD leave blank 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 additional 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 42] RFC 3801 VPIMv2 June 2004

 6.  Other un-profiled contents MUST only be sent by bilateral
     agreement.
 7.  If fax is supported.
 8.  If the fax content cannot be presented it MAY be dropped.
 9.  Handling of a vCard in text/directory is no longer defined.

13. 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, spoken
 subject 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

Vaudreuil & Parsons Standards Track [Page 43] RFC 3801 VPIMv2 June 2004

–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==

–MessageBoundary Content-type: Audio/32KADPCM Content-Transfer-Encoding: Base64 Content-Disposition: inline; voice=Spoken-Subject Content-Language: en-US Content-ID: part2@VM2-4321

glslfdslsertiflkTfpgkTportrpkTpfgTpoiTpdadasssdasddasdasd (This is a sample of the base-64 Spoken Subject data) fgdhgddlkgpokpeowrit09==

–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==

–MessageBoundary- - - -

The following message is a forwarded single segment voice. Both the forwarded message and the forwarding message contain the senders 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

Vaudreuil & Parsons Standards Track [Page 44] RFC 3801 VPIMv2 June 2004

  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==

Vaudreuil & Parsons Standards Track [Page 45] RFC 3801 VPIMv2 June 2004

  1. -MessageBoundary

Content-type: Message/RFC822

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

Vaudreuil & Parsons Standards Track [Page 46] RFC 3801 VPIMv2 June 2004

 The following example is for a DSN sent to the sender of a message 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
    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

Vaudreuil & Parsons Standards Track [Page 47] RFC 3801 VPIMv2 June 2004

  1. -RAA14128.773615765/VM1.COMPANY.COM

content-type: Message/RFC822

    [original VPIM message goes here]
  1. -RAA14128.773615765/VM1.COMPANY.COM–
 The following example is for an MDN sent to the original sender for a
 message that 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 Content-Type: multipart/report;

      Report-type=disposition-notification;
      Boundary="RAA14128.773615765/EXCHANGE.COMPANY.COM"

–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==

–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

–RAA14128.773615765/EXCHANGE.COMPANY.COM Content-type: Message/RFC822

[original VPIM message goes here]

–RAA14128.773615765/EXCHANGE.COMPANY.COM–

Vaudreuil & Parsons Standards Track [Page 48] RFC 3801 VPIMv2 June 2004

14. Appendix C - Example Error Voice Processing Error Codes

 The following common voice processing errors and their corresponding
 status codes are given as examples.  The text after the error codes
 is 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          4.4.1 Persistent connection error
    because remote system is busy         - busy
    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 49] RFC 3801 VPIMv2 June 2004

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

15. 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

16. Appendix E - IANA Registrations

 There are no changes to the registration per [DISP] of the voice
 content disposition parameter defined in the earlier VPIM V2
 document, RFC 2421.  There are no changes to the registration per
 [MIME4] of the Multipart/voice-message content type defines in the
 earlier VPIM v2 document, RFC 2423.
 Both are presented here for information.

Vaudreuil & Parsons Standards Track [Page 50] RFC 3801 VPIMv2 June 2004

16.1. 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,
       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.

16.2. Multipart/Voice-Message MIME Media Type Definition

 To: ietf-types@iana.org
 Subject: Registration of MIME media type
          Multipart/voice-message
 MIME media type name: multipart
 MIME subtype name: voice-message
 Required parameters: boundary, version
    The use of boundary is defined in [MIME2]

Vaudreuil & Parsons Standards Track [Page 51] RFC 3801 VPIMv2 June 2004

    The version parameter that contains the value "2.0" if
    enclosed content conforms to [VPIM2R2].  The absence of this
    parameter indicates conformance to the previous version
    defined in RFC 1911 [VPIM1].
 Optional parameters: none
 Encoding considerations: 7bit, 8bit or Binary
 Security considerations:
    This definition identifies the content as being a voice
    message.  In some environments (though likely not the
    majority), the loss of the anonymity of the content may be a
    security issue.
 Interoperability considerations:
    Systems developed to conform with [VPIM1] may not conform to
    this registration.  Specifically, the required version will
    likely be absent, in this case the recipient system should
    still be able to accept the message and will be able to
    handle the content.  The VPIM v1 positional identification,
    however, would likely be lost.
 Published specification:
    This document
    Applications that use this media type:
    Primarily voice messaging
    Additional information:
    Magic number(s): none
    File extension(s): .VPM
    Macintosh File Type Code(s): VPIM
 Person & email address to contact for further information:
    Glenn W. Parsons
    gparsons@nortelnetworks.com
    Gregory M. Vaudreuil
    gregv@ieee.org
 Intended usage: COMMON

Vaudreuil & Parsons Standards Track [Page 52] RFC 3801 VPIMv2 June 2004

 Author/Change controller:
    Glenn W. Parsons & Gregory M. Vaudreuil

17. Appendix F - Change History: RFC 2421 (VPIM V2) to this Document

 The updated profile in this document is based on the implementation
 and operational deployment experience of several vendors.  The
 changes are categorized as general, content, transport and
 conformance.  They are summarized below:
 1. General
  1. Various and substantial editorial updates to improve

readability.

  1. Separated send rules from receive rules to aid clarity.
  1. Clarified the behavior upon reception of unrecognized content

types expected with the interworking between voice and unified

      messaging systems.  (E.g., Unsupported non-audio contents should
      be discarded to deliver the audio message.)
  1. Reworked the sensitivity requirements to align them with X.400.

Eliminated dependencies upon the MIXER documents.

  1. Reorganized the content-type descriptions for clarity
 2. Content
  1. Changed handling of received lines by a gateway to SHOULD NOT

delete in a gateway. In gateways to systems such as AMIS, it is

      not possible to preserve this information.  It is intended that
      such systems be able to claim conformance.
  1. Eliminated the vCard as a supported VPIM V2 content type.
  1. Merged in text from RFC 2423 (Multipart/voice-message)
 3. Transport
  1. None
 4. Conformance
  1. Aligned the table of Appendix A to the requirements in the text.

Vaudreuil & Parsons Standards Track [Page 53] RFC 3801 VPIMv2 June 2004

18. Authors' Addresses

 Gregory M. Vaudreuil
 Lucent Technologies
 7291 Williamson Rd
 Dallas, TX  75214
 United States
 EMail: gregv@ieee.org
 Glenn W. Parsons
 Nortel Networks
 P.O. Box 3511, Station C
 Ottawa, ON  K1Y 4H7
 Canada
 Phone: +1-613-763-7582
 Fax: +1-613-763-2697
 EMail: GParsons@NortelNetworks.com

Vaudreuil & Parsons Standards Track [Page 54] RFC 3801 VPIMv2 June 2004

19. Full Copyright Statement

 Copyright (C) The Internet Society (2004).  This document is subject
 to the rights, licenses and restrictions contained in BCP 78, and
 except as set forth therein, the authors retain all their rights.
 This document and the information contained herein are provided on an
 "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
 OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
 ENGINEERING TASK FORCE DISCLAIM 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.

Intellectual Property

 The IETF takes no position regarding the validity or scope of any
 Intellectual Property Rights or other rights that might be claimed to
 pertain to the implementation or use of the technology described in
 this document or the extent to which any license under such rights
 might or might not be available; nor does it represent that it has
 made any independent effort to identify any such rights.  Information
 on the procedures with respect to rights in RFC documents can be
 found in BCP 78 and BCP 79.
 Copies of IPR disclosures made to the IETF Secretariat and any
 assurances of licenses to be made available, or the result of an
 attempt made to obtain a general license or permission for the use of
 such proprietary rights by implementers or users of this
 specification can be obtained from the IETF on-line IPR repository at
 http://www.ietf.org/ipr.
 The IETF invites any interested party to bring to its attention any
 copyrights, patents or patent applications, or other proprietary
 rights that may cover technology that may be required to implement
 this standard.  Please address the information to the IETF at ietf-
 ipr@ietf.org.

Acknowledgement

 Funding for the RFC Editor function is currently provided by the
 Internet Society.

Vaudreuil & Parsons Standards Track [Page 55]

/data/webs/external/dokuwiki/data/pages/rfc/rfc3801.txt · Last modified: 2004/06/15 19:31 (external edit)