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rfc:rfc1911

Network Working Group G. Vaudreuil Request for Comments: 1911 Octel Network Services Category: Experimental February 1996

                  Voice Profile for Internet Mail

Status of this Memo

 This memo defines an Experimental Protocol for the Internet
 community.  This memo does not specify an Internet standard of any
 kind.  Discussion and suggestions for improvement are requested.
 Distribution of this memo is unlimited.

1. Abstract

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

2. Scope and Design Goals

 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
 including voice and facsimile.
 This document specifies a profile of the TCP/IP multimedia messaging
 protocols for use by special-purpose voice processing platforms.
 These platforms have historically been special-purpose computers and
 often do not have facilities normally associated with a traditional
 Internet Email-capable computer.  This profile is intended to specify
 the minimum common set of features and functionally for conformant

Vaudreuil Experimental [Page 1] RFC 1911 MIME Voice Profile February 1996

 systems.
 The voice profile does not place limits on the use of additional
 media types or protocol options.  However, systems which are
 conformant to this profile should not send messages with features
 beyond this profile unless explicit per-destination configuration of
 these enhanced features is provided.  Such configuration information
 could be stored in a directory, though the implementation of this is
 a local matter.
 The following are typical limitations of voice messaging platform
 which were considered in creating this baseline profile.
    1) Text messages are not normally received and often cannot be
    displayed or viewed.  They can often be processed only via
    advanced text-to-speech or text-to-fax features not currently
    present in these machines.
    2) Voice mail machines usually act as an integrated Message
    Transfer Agent and a User Agent.  The voice mail machine is
    responsible for final delivery, and there is no relaying of
    messages.  RFC 822 header fields may have limited use in the
    context of the simple messaging features currently deployed.
    3) VM message stores are generally not capable of preserving the
    full semantics of an Internet message.  As such, use of a voice
    mail machine for general message forwarding and gatewaying is not
    supported.  Storage of "Received" lines and "Message-ID" may be
    limited.
    4) Nothing in this document precludes use of a general purpose
    email gateway from providing these services.  However, significant
    performance degradation may result if the email gateway does not
    support the ESMTP options recommended by this document.
    5) Internet-style mailing lists are not generally supported.
    Distribution lists are implemented as local alias lists.
    6) There is generally no human operator.  Error reports must be
    machine-parsable so that helpful responses can be given to users
    whose only access mechanism is a telephone.
    7) The system user names are often limited to 16 or fewer numeric
    characters.  Alpha characters are not generally used for mailbox
    identification as they cannot be easily entered from a telephone
    terminal.

Vaudreuil Experimental [Page 2] RFC 1911 MIME Voice Profile February 1996

 It is a goal of this effort to make as few restrictions and additions
 to the existing Internet mail protocols as possible while satisfying
 the user requirements for interoperability with current voice
 messaging systems.  This goal is motivated by the desire to increase
 the accessibility to digital messaging by enabling the use of proven
 existing networking software for rapid development.
 This specification is intended for use on a TCP/IP network, however,
 it is possible to use the SMTP protocol suite over other transport
 protocols.  The necessary protocol parameters for such use is outside
 the scope of this document.
 This profile is intended to be robust enough to be used in an
 environment such as the global Internet with installed base gateways
 which do not understand MIME.  It is expected that a messaging system
 will be managed by a system administrator who can perform TCP/IP
 network configuration.  When using facsimile or multiple voice
 encodings, it is expected that the system administrator will 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 this directory
 listing capabilities is a local matter.
 This specification is a profile of the relevant TCP/IP Internet
 protocols.  These technologies, as well as the specifications for the
 Internet mail protocols, are defined in the Request for Comment (RFC)
 document series.  That series documents the standards as well as the
 lore of the TCP/IP protocol suite.  This document should be read with
 the following RFC documents: RFC 821, Simple Mail Transfer Protocol;
 RFC 822, Standard for the format of ARPA Internet Messages; RFC 1521
 and RFC 1522, Multipurpose Internet Mail Extensions; RFC 1651, RFC
 1652, and RFC 1653, SMTP Service Extensions (ESMTP); and RFC 1034 and
 RFC 1035, Domain Name System. Where additional functionality is
 needed, it will be defined in this document or in an appendix.

3. Protocol Restrictions

 This protocol does not limit the number of recipients per message.
 Where possible, 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.  However, ESMTP currently does
 not provide a mechanism for indicating the number of supported
 recipients.

Vaudreuil Experimental [Page 3] RFC 1911 MIME Voice Profile February 1996

 This protocol does not limit the maximum message length.
 Implementors should understand that some machines will be unable to
 accept excessively long messages.  A mechanism is defined in the RFC
 1425 ESMTP extensions to declare the maximum message size supported.
 The message size indicated in the ESMTP SIZE command is in bytes, not
 minutes.  The number of bytes varies by voice encoding format and
 must include the MIME wrapper overhead.  If the length must be known
 before sending, an approximate translation into minutes can be
 performed if the voice encoding is known.

4. Voice Message Interexchange Format

 The voice message interchange format is a profile of the Internet
 Email Protocol Suite.  It requires components from the message format
 standard for Internet messages [RFC822], the Multipurpose Internet
 Message Extensions [MIME], the X.400 gateway specification [X.400],
 and the delivery report specifications [DRPT][STATUS].

4.1 Message Addressing Formats

 The RFC 822 uses 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.
 The local part of the address shall be an ASCII string uniquely
 identifying a mailbox on a destination system.  For voice messaging,
 the local part is a printable string containing the mailbox ID of the
 originator or recipient.  Administration of this space is expected to
 conform to national or corporate private telephone numbering plans.
 While alpha characters and long mailbox identifiers are permitted,
 most voice mail networks rely on numeric mailbox identifiers to
 retain compatibility with the limited 10 digit telephone keypad.
 For example, a compliant message may contain the address
 2145551212@mycompany.com. It should be noted that while the example
 mailbox address is based on the North American Numbering Plan, any
 other corporate numbering plan can be used.  The use of the domain
 naming system should be transparent to the user.  It is the
 responsibility of the voice mail machine to lookup the fully-
 qualified domain name (FQDN) based on the address entered by the
 user.  The mapping of dialed address to final destination system is
 generally accomplished through implementation-specific means.
 Special addresses are provided for compatibility with the conventions
 of the Internet mail system and to facilitate testing.  These
 addresses do not use numeric local addresses, both to conform to

Vaudreuil Experimental [Page 4] RFC 1911 MIME Voice Profile February 1996

 current Internet practice and to avoid conflict with existing numeric
 addressing plans.  Some special addresses are 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 a individual
 implementation choice.
 Loopback@domain
 A special mailbox name named "loopback" SHOULD be designated for
 loopback testing.  If supported, all messages sent to this mailbox
 MUST be returned back to the address listed in the From: address as a
 new message.  The originating address of the returned address MUST be
 "postmaster" to prevent mail loops.
 These two addresses are RESERVED so they do not conflict with any
 internal addressing plan.

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, headers do not indicate delivery options for the
 transport of messages.
 The following header lines are permitted for use with voice messages.
 From
 The originator's fully-qualified domain address (a mailbox address
 followed by the fully-qualified domain name).  The user listed in
 this field should be presented in the voice message envelope as the
 originator of the message.
 Systems conformant to this profile SHOULD provide the text personal
 name of the sender in a quoted phrase if available.  To facilitate
 storage of the text name in a local dial-by-name cache directory, the
 first and last name MUST be separable.  Text names in voice messages
 MUST be represented in the form "last, first, mi." [822].

Vaudreuil Experimental [Page 5] RFC 1911 MIME Voice Profile February 1996

   Example:
     From: "User, Joe S." <2145551212@mycompany.com>
   To
 The TO header contains the recipient's fully-qualified domain
 address.  There may be one or more To: fields in any message.
 Systems conformant to this profile SHOULD provide the text personal
 name of the recipient, if known, in a quoted phrase.  The name MUST
 be in the form "last, first, mi." [822].
   Example:
     To: "User, Sam S." <2145551213@mycompany.com>
 Cc
 The CC header contains additional recipients' fully-qualified domain
 addresses. Many voice mail systems are not capable of storing or
 reporting the full list of recipients to the receiver.
 Systems conformant to this profile SHOULD provide the text personal
 name of the recipient, if known, in a quoted phrase.  The name MUST
 be in the form "last, first, mi." [822].
   Example:
     To: "User, Sam S." <2145551213@mycompany.com>
 Systems conformant to this profile may discard the CC list of
 incoming messages as necessary.  Systems conformant to this profile
 should provide a complete list of recipients when possible.
 Date
 The Date header contains the date, time, and time zone in which the
 message was sent by the originator.  Conforming implementations
 SHOULD be able to convert RFC 822 date and time stamps into local
 time.
   Example:
     Date: Wed, 28 Jul 93 10:08:49 PST
 The sending system MUST report the time the message was sent [822].

Vaudreuil Experimental [Page 6] RFC 1911 MIME Voice Profile February 1996

 Sender
 The Sender header contains the actual address of the originator if
 the message is sent by an agent on behalf of the author indicated in
 the From: field.  Support for this field cannot be assumed when
 talking to a voice system and SHOULD NOT be generated by a conforming
 implementation.
 While it may not be possible to save this information in some voice
 mail machines, discarding this information or the ESMTP MAIL FROM
 address will make it difficult to send an error message to the proper
 destination [822].
 Message-id
 The Message-id header contains a unique per-message identifier.  A
 unique message-id MUST be generated for each message sent from a
 conforming implementation.
 The message-id is not required to be stored on the receiving system.
 This identifier MAY be used for tracking, auditing, and returning
 read-receipt reports [822].
   Example:
     Message-id: <12345678@mycompany.com>
 Received
 The Received header contains trace information added to the beginning
 of a RFC 822 message by message transport agents (MTA).  This is the
 only header permitted to be added by an MTA.  Information in this
 header is useful for debugging when using an ASCII message reader or
 a header parsing tool.
 A conforming system MUST add Received headers when acting as a
 gateway and must not remove them.  These headers MAY be ignored or
 deleted when the message is received at the final destination [822].
 MIME Version
 The MIME-Version header indicates that the message is conformant to
 the MIME message format specification. Systems conformant to the
 voice messaging profile MUST include a comment with the words "(Voice
 1.0)" [MIME].

Vaudreuil Experimental [Page 7] RFC 1911 MIME Voice Profile February 1996

   Example:
     MIME-Version: 1.0 (Voice 1.0)
 Content-Type
 The content-type header declares the type of content enclosed in the
 message.  One of the allowable contents is multipart, a mechanism for
 bundling several message components into a single message.  The
 allowable contents are specified in the next section of this document
 [MIME].
 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.  Conformant implementations MUST recognize and decode the
 standard encodings, "Binary", "7bit, "8bit", "Base-64" and "Quoted-
 Printable".  The allowable content-transfer-encodings are specified
 in the next section of this document [MIME].
 Sensitivity
 The sensitivity header, if present, indicates the requested privacy
 level.  The case-insensitive values "Personal" and "Private" are
 specified. If no privacy is requested, this field is omitted.
 If a sensitivity header is present in the message, a conformant
 system MUST prohibit the recipient from forwarding this message to
 any other user.  If the receiving system does not support privacy and
 the sensitivity is one of "Personal" or "Private", the message MUST
 be returned to the sender with an appropriate error code indicating
 that privacy could not be assured and that the message was not
 delivered [X400].
 Importance
 Indicates the requested priority to be given by the receiving system.
 The case-insensitive values "low", "normal" and "high" are specified.
 If no special importance is requested, this header may be omitted and
 the value assumed to be "normal".
 Conformant implementations MAY use this header to indicate the
 importance of a message and may order messages in a recipient's
 mailbox [X400].

Vaudreuil Experimental [Page 8] RFC 1911 MIME Voice Profile February 1996

 Subject
 The subject field is often provided by email systems but is not
 widely supported on Voice Mail platforms. This field MAY be generated
 by a conforming implementation and may be discarded if present by a
 receiving system [822].

4.3 Message Content Types

 MIME is a general-purpose message body format that is extensible to
 carry a wide range of body parts.  The basic protocol is described in
 [MIME].  MIME also provides for encoding binary data so that it can
 be transported over the 7-bit text-oriented SMTP protocol.  This
 transport encoding is independent of the audio encoding designed 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 ("Base-64").
 While Base-64 is dramatically more efficient for audio data, both
 will work.  Where binary transport is available, no transport
 encoding is needed, and the data can be labeled as "Binary".
 An implementation in conformance with this profile SHOULD send audio
 data in binary form when binary message transport is available.  When
 binary transport is not available, implementations MUST encode the
 message as Base-64.  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.
 The following content types are identified for use with this profile.
 Note that each of these contents can be sent individually in a
 message or wrapped in a multipart message to send multi-segment
 messages.
 Message/RFC822
 MIME requires support of the Message/RFC822 message encapsulation
 body part.  This body part is used in the Internet to forward
 complete messages within a multipart/mixed message.  Processing of
 this body part entails trivial processing to decapsulate/encapsulate
 the message.  Systems conformant to this profile SHOULD NOT send this
 body part but MUST accept if in conformance with basic MIME.
 Specific handling depends on the platform, and interpretation of this
 content-type is left as an implementation decision [MIME].

Vaudreuil Experimental [Page 9] RFC 1911 MIME Voice Profile February 1996

 Text/Plain
 MIME requires support of the basic Text/Plain content type.  This
 content type has no applicability within the voice messaging
 environment.  Conformant implementations MUST NOT send the Text/Plain
 content-type.  Conformant implementations MUST accept Text/Plain
 messages, however, specific handling is left as an implementation
 decision.  One option is to return the message to the sender with a
 media-unsupported error code [MIME].
 Multipart/Mixed
 MIME provides the facilities for enclosing several body parts in a
 single message. Multipart/Mixed MAY be used for sending multi-segment
 voice messages, that is, to preserve across the network the
 distinction between an annotation and a forwarded message.
 Conformant systems MUST accept multipart/mixed body parts.  Systems
 MAY to collapse such a multi-segment message into a single segment if
 multi-segment messages are not supported on the receiving machine
 [MIME].
 Message/Notification
 This MIME body part is used for sending machine-parsable delivery
 status notifications.  Conformant implementations must use the
 Message/Notification construct when returning messages or sending
 warnings.  Conformant implementations must recognize and decode the
 Message/Notification content type and present the reason for failure
 to the user [NOTIFY].
 Multipart/Report
 The Multipart/Report is used for enclosing a Message/Notification
 body part and any returned message content.  This body type is a
 companion to Message/Notification.  Conformant implementations must
 use the Multipart/Report construct when returning messages or sending
 warnings.  Conformant implementations must recognize and decode the
 Multipart/Report content type [REPORT].
 Audio/32KADPCM
 CCITT Recommendation G.721 [G721] describes the algorithm recommended
 for conversion of a 64 KB/s A-law or u-law PCM channel to and from a
 32 KB/s channel.  The conversion is applied to the PCM stream using
 an Adaptive Differential Pulse Code Modulation (ADPCM) transcoding
 technique. This algorithm will be registered with the IANA for MIME
 use under the name Audio/32KADPCM.

Vaudreuil Experimental [Page 10] RFC 1911 MIME Voice Profile February 1996

 An implementation conformant to this profile MUST use Audio/32KADPCM
 by default.
 Proprietary Voice Formats
 Proprietary voice encoding formats or other standard formats may be
 supported under this profile provided a unique identifier is
 registered with the IANA prior to use.  These encodings should be
 registered as sub-types of Audio.
 Use of any other encoding except Audio/32KADPCM reduces
 interoperability in the absence of explicit manual system
 configuration.  A conformant implementation MAY use any other
 encoding with explicit per-destination configuration.
 Multipart/Voice-Message
 This new MIME multipart structure provides a mechanism for packaging
 the senders spoken name, a spoken subject and, the message.  The
 multipart provides for the packaging of three segments, the first is
 the spoken name, the second is a spoken subject, and the third is the
 message itself.  Forwarded messages can be created by simply nesting
 multipart content-types (this is also possible with Multipart/Mixed
 if spoken name or spoken subject is not present).  This type is
 defined in an appendix to this document.
 Conforming implementations MUST send the Multipart/Voice-Message if a
 spoken name or spoken subject is available.  Conforming
 implementations SHOULD recognize the Multipart/Voice-Message and
 separate the spoken name or spoken subject.

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 networking protocols.
 ESMTP is a general-purpose messaging protocol, designed both to send
 mail and to allow terminal console messaging.  Simple Mail Transport
 Protocol (SMTP) was originally created for the exchange of US-ASCII
 7-bit text messages.  Binary and 8-bit text messages have
 traditionally been transported by encoding the messages into a 7-bit
 text-like form.  [ESMTP] was recently published and formalized an
 extension mechanism for SMTP, and subsequent RFCs have defined 8-bit

Vaudreuil Experimental [Page 11] RFC 1911 MIME Voice Profile February 1996

 text networking, binary networking, and extensions to permit the
 declaration of message size for the efficient transmission of large
 messages such as multi-minute voice mail.
 A command streaming extension for high performance message
 transmission has been defined [PIPE].  This extension reduces the
 number of round-trip packet exchanges and makes it possible to
 validate all recipient addresses in one operation.  This extension is
 optional but recommended.
 The following sections list ESMTP commands, keywords, and parameters
 that are required and those that are optional.

5.1 ESMTP Commands

 HELO
 Base SMTP greeting and identification of sender.  This command is not
 to be sent by conforming systems unless the more-capable EHLO command
 is not accepted.  It is included for compatibility with general SMTP
 implementations. Conforming implementations MUST implement the HELO
 command for backward compatibility but SHOULD NOT send it unless EHLO
 is not supported [SMTP].
 MAIL FROM (REQUIRED)
 Originating mailbox.  This address contains the mailbox to which
 errors should be sent.  This address may not be the same as the
 message sender listed in the message header fields if the message was
 received from a gateway or sent to an Internet-style mailing list.
 Conforming implementations MUST implement the extended MAIL FROM
 command [SMTP, ESMTP].
 RCPT TO
 Recipient's mailbox.  This field contains only the addresses to which
 the message should be delivered for this transaction.  In the event
 that multiple transport connections to multiple destination machines
 are required for the same message, this list may not match the list
 of recipients in the message header. Conforming implementations MUST
 implement the extended RCPT TO command [SMTP, ESMTP].
 DATA
 Initiates the transfer of message data.  Support for this command is
 required in the event the binary mode command BDAT is not supported
 by the remote system.  Conforming implementations MUST implement the
 SMTP DATA command for backwards compatibility [SMTP].

Vaudreuil Experimental [Page 12] RFC 1911 MIME Voice Profile February 1996

 TURN
 Requests a change-of-roles, that is, the client that opened the
 connection offers to assume the role of server for any mail the
 remote machine may wish to send.  Because SMTP is not an
 authenticated protocol, the TURN command presents an opportunity to
 improperly fetch mail queued for another destination.  Conforming
 implementations SHOULD NOT implement the TURN command [SMTP].
 QUIT
 Requests that the connection be closed.  If accepted, the remote
 machine will reset and close the connection.  Conforming
 implementations MUST implement the QUIT command [SMTP].
 RSET
 Resets the connection to its initial state.  Conforming
 implementations MUST implement the RSET command [SMTP].
 VRFY
 Requests verification that this node can reach the listed recipient.
 While this functionality is also included in the RCPT TO command,
 VRFY allows the query without beginning a mail transfer transaction.
 This command is useful for debugging and tracing problems.
 Conforming implementations MAY implement the VRFY command [SMTP].
 (Note that the implementation of VRFY may simplify the guessing of a
 recipient's mailbox or automated sweeps for valid mailbox addresses,
 resulting in a possible reduction in privacy.  Various implementation
 techniques may be used to reduce the threat, such as limiting the
 number of queries per session [SMTP].)
 EHLO
 The enhanced mail greeting that enables a server to announce support
 for extended messaging options.  The extended messaging modes are
 discussed in a later section of this document.  Conformant
 implementations MUST implement the ESMTP command and return the
 capabilities indicated later in this memo [ESMTP].
 BDAT
 The BDAT command provides a higher efficiency alternative to the
 earlier DATA command, especially for voice. The BDAT command provides
 for native binary transport.  Because voice messages are large binary
 objects otherwise subject to BASE-64 encoding, BDAT will result in a

Vaudreuil Experimental [Page 13] RFC 1911 MIME Voice Profile February 1996

 substantial improvement in transmission efficiency over DATA.
 Conformant implementations SHOULD support binary transport using the
 BDAT command [BINARY].

5.2 ESMTP Capabilities

 The following ESMTP keywords indicate extended features useful for
 voice messaging.
 PIPELINING
 The "PIPELINING" keyword indicates ability of the receiving SMTP to
 accept pipelined commands.  Pipelining commands dramatically improves
 the protocol performance over wide area networks.  Conformant
 implementations SHOULD support the command pipelining indicated by
 this parameter [PIPE].
 SIZE
 The "SIZE" keyword provides a mechanism by which the receiving SMTP
 can indicate the maximum size message supported.  Conformant
 implementations MUST provide the size capability and SHOULD honor any
 size limitations when sending [SIZE].
 CHUNKING
 The "CHUNKING" keyword indicates that the receiver will support the
 high-performance binary transport mode.  Note that CHUNKING can be
 used with any message format and does not imply support for binary
 encoded messages. Conformant implementations SHOULD support binary
 transport indicated by this capability [BINARY].
 BINARYMIME
 The "BINARYMIME" keyword indicates that the receiver SMTP can accept
 binary encoded MIME messages. Conformant implementations should
 support binary transport indicated by this capability [BINARY].
 NOTIFY
 The "NOTIFY" keyword indicates that the receiver SMTP will accept
 explicit delivery status notification requests.  Conformant
 implementations MUST support the delivery notification extensions in
 [DSN].

Vaudreuil Experimental [Page 14] RFC 1911 MIME Voice Profile February 1996

5.3 ESMTP Parameters - MAIL FROM

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

5.4 ESMTP Parameters - RCPT TO

 NOTIFY
 The NOTIFY parameter indicates the conditions under which a delivery
 report SHOULD be sent. Conformant implementations must honor this
 request [DSN].
 RET
 The RET parameter indicates whether the content of the message should
 be returned.  Conformant systems SHOULD honor a request for returned
 content [DSN].

6. Management Protocols

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

6.1 Network Management

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

6.2 Directory and Message Management

 Conformant systems SHOULD provide for the management of message
 traffic and queue monitoring based on the Message and Directory MIB
 [MADMAN].

7. References

[MIME] Borenstein, N., and N. Freed, "Multipurpose Internet Mail
       Extensions", RFC 1521, Bellcore, Innosoft, September 1993.
[MSG822] Crocker, D., "Standard for the Format of ARPA Internet Text
         Messages", STD 11, RFC 822, UDEL, August 1982.

Vaudreuil Experimental [Page 15] RFC 1911 MIME Voice Profile February 1996

[X400] Hardcastle-Kille, S., "Mapping between X.400(1988) / ISO
       10021 and RFC 822", RFC 1327, UCL, May 1992.
[PIPE] Freed, N., and A. Cargille, "SMTP Service Extension for
       Command Pipelining", RFC 1854, October 1995.
[ESMTP] Klensin, J., Freed, N., Rose, M., Stefferud, E., and D.
        Crocker, "SMTP Service Extensions", RFC 1869, United Nations
        University, Innosoft International, Inc., Dover Beach
        Consulting, Inc., Network Management Associates, Inc., The
        Branch Office, November 1995.
[SIZE] Klensin, J, Freed, N., Moore, K, "SMTP Service Extensions for
       Message Size Declaration", RFC 1870, United Nations
       University, Innosoft International, Inc., November 1995.
[8BIT] Klensin, J., Freed, N., Rose, M., Stefferud, E., D. Crocker,
       "SMTP Service Extension for 8bit-MIMEtransport", RFC 1426,
       United Nations University, Innosoft International, Inc.,
       Dover Beach Consulting, Inc., Network Management Associates,
       Inc., The Branch Office, February 1993.
[DNS1] Mockapetris, P., "Domain Names - Implementation and
       Specification", STD 13, RFC 1035, USC/Information Sciences
       Institute, November 1987.
[DNS2] Mockapetris, P., "Domain Names - Concepts and Facilities",
       STD 13, RFC 1034, USC/Information Sciences Institute,
       November 1987.
[SMTP] Postel, J., "Simple Mail Transfer Protocol", STD 10, RFC 821,
       USC/Information Sciences Institute, August 1982.
[BINARY] Vaudreuil, G., "SMTP Service Extensions for Transmission of
         Large and Binary MIME Messages", RFC 1830, Octel Network
         Services, October 1995.
[NOTIFY] Moore, K., and G. Vaudreuil, "An Extensible Message
         Format for Delivery Status Notifications", RFC 1894,
         University of Tennessee, Octel Network Services, January
         1996.
[REPORT] Vaudreuil, G., "The Multipart/Report Content Type for the
         Reporting of Mail System Administrative Messages", RFC
         1892, Octel Network Services, January 1996.

Vaudreuil Experimental [Page 16] RFC 1911 MIME Voice Profile February 1996

[DSN] Moore, K., "SMTP Service Extensions for Delivery Status
      Notifications", RFC 1891, University of Tennessee, January
      1996.
[G721] CCITT Recommendation G.700-G.795 (1988), General Aspects of
       Digital Transmission Systems, Terminal Equipment.  Blue Book.
[MADMAN] Freed, N., and S. Kille, "Mail Monitoring MIB", RFC 1566,
         January 1994.
[MIB II] Rose, M., "Management Information Base for Network
         Management of TCP/IP-based internets: MIB-II", RFC 1158,
         May 1990.

8. Security Consideration

 This document is a profile of existing Internet mail protocols.  As
 such, it does not create any security issues not already existing in
 the profiled Internet mail protocols themselves.

9. Acknowledgments

 The author would like to offer special thanks to Glenn Parsons/BNR
 for his extensive review, helpful suggestions, and extensive editing
 including the requirements matrix.

10. Author's Address

 Gregory M. Vaudreuil
 Octel Network Services
 17080 Dallas Parkway
 Dallas, TX 75248-1905
 Phone/Fax: +1-214-733-2722
 EMail: Greg.Vaudreuil@Octel.Com

Vaudreuil Experimental [Page 17] RFC 1911 MIME Voice Profile February 1996

11. Appendix - MIME/ESMTP Voice Profile Requirements Summary

                                             |          | | | |S| |
                                             |          | | | |H| |F
                                             |          | | | |O|M|o
                                             |          | |S| |U|U|o
                                             |          | |H| |L|S|t
                                             |          |M|O| |D|T|n
                                             |          |U|U|M| | |o
                                             |          |S|L|A|N|N|t
                                             |          |T|D|Y|O|O|t
  FEATURE                                    |SECTION   | | | |T|T|e
  -------------------------------------------|----------|-|-|-|-|-|-
                                             |          | | | | | |
  Message Addressing Formats:                |          | | | | | |
    Use DNS host names                       |4.1       |x| | | | |
    Use only numbers in mailbox IDs          |4.1       | |x| | | |
    Use alpha-numeric mailbox IDs            |4.1       | | |x| | |
    Support of postmaster@domain             |4.1       | |x| | | |
    Support of loopback@domain               |4.1       | |x| | | |
                                             |          | | | | | |
  Message Header Fields:                     |          | | | | | |
    Encoding outbound messages               |          | | | | | |
      From                                   |4.2       |x| | | | |
        Addition of text personal name       |4.2       | |x| | | |
      To                                     |4.2       |x| | | | |
        Addition of text personal name       |4.2       | |x| | | |
      CC                                     |4.2       | | |x| | |
      Date                                   |4.2       |x| | | | |
      Sender                                 |4.2       | | | |x| |
      Message-id                             |4.2       | |x| | | |
      Received                               |4.2       |x| | | | |
      MIME Version: 1.0 (Voice 1.0)          |4.2       |x| | | | |
      Content-Type                           |4.2       |x| | | | |
      Content-Transfer-Encoding              |4.2       |x| | | | |
      Sensitivity                            |4.2       | | |x| | |
      Importance                             |4.2       | | |x| | |
      Subject                                |4.2       | | |x| | |
    Detection & Decoding inbound messages    |          | | | | | |
      From                                   |4.2       |x| | | | |
        Utilize text personal name           |4.2       | |x| | | |
      To                                     |4.2       |x| | | | |
        Utilize text personal name           |4.2       | | |x| | |
      CC                                     |4.2       | | |x| | |
        Utilize text personal name           |4.2       | | |x| | |
      Date                                   |4.2       |x| | | | |
        Conversion of Date to local time     |4.2       | |x| | | |
      Sender                                 |4.2       | | | |x| |

Vaudreuil Experimental [Page 18] RFC 1911 MIME Voice Profile February 1996

      Message ID                             |4.2       |x| | | | |
      Received                               |4.2       | |x| | | |
      MIME Version: 1.0 (Voice 1.0)          |4.2       |x| | | | |
      Content Type                           |4.2       |x| | | | |
      Content-Transfer-Encoding              |4.2       |x| | | | |
      Sensitivity                            |4.2       |x| | | | |1
      Importance                             |4.2       | | |x| | |
      Subject                                |4.2       | | |x| | |
                                             |          | | | | | |
  Binary Content Encoding:                   |          | | | | | |
    Encoding outbound messages               |          | | | | | |
      7BITMIME                               |4.3       | | | | |x|
      8BITMIME                               |4.3       | | | | |x|
      Quoted Printable                       |4.3       | | | | |x|
      Base-64                                |4.3       |x| | | | |2
      Binary                                 |4.3       |x| | | | |3
    Detection & decoding inbound messages    |          | | | | | |
      7BITMIME                               |4.3       |x| | | | |
      8BITMIME                               |4.3       |x| | | | |
      Quoted Printable                       |4.3       |x| | | | |
      Base-64                                |4.3       |x| | | | |
      Binary                                 |4.3       |x| | | | |
                                             |          | | | | | |
  Message Content Types:                     |          | | | | | |
    Inclusion in outbound messages           |          | | | | | |
      Message/RFC822                         |4.3       | | | |x| |
      Text/plain                             |4.3       | | | | |x|
      Multipart/Mixed                        |4.3       | | |x| | |
      Message/Notification                   |4.3       |x| | | | |
      Multipart/Report                       |4.3       |x| | | | |
      Audio/32KADPCM                         |4.3       |x| | | | |
      Audio/* (proprietary encodings)        |4.3       | | |x| | |
      Multipart/Voice-Message                |4.3       |X| | | | |
    Detection & decoding in inbound messages |          | | | | | |
      Message/RFC822                         |4.3       |x| | | | |
      Text/plain                             |4.3       |x| | | | |
      Multipart/Mixed                        |4.3       |x| | | | |
      Message/Notification                   |4.3       |x| | | | |
      Multipart/Report                       |4.3       |x| | | | |
      Audio/32KADPCM                         |4.3       |x| | | | |
      Audio/* (proprietary encodings)        |4.3       | | |x| | |
      Multipart/Voice-Message                |4.3       |X| | | | |
                                             |          | | | | | |
  Message Transport Protocol:                |          | | | | | |
    ESMTP Commands                           |          | | | | | |
      HELO                                   |5.1       |x| | | | |
      MAIL FROM                              |5.1       |x| | | | |
      RCPT TO                                |5.1       |x| | | | |

Vaudreuil Experimental [Page 19] RFC 1911 MIME Voice Profile February 1996

      DATA                                   |5.1       |x| | | | |
      TURN                                   |5.1       | | | | |x|
      QUIT                                   |5.1       |x| | | | |
      RSET                                   |5.1       |x| | | | |
      VRFY                                   |5.1       | | |x| | |
      EHLO                                   |5.1       |x| | | | |
      BDAT                                   |5.1       | |x| | | |3
    ESMTP Keywords                           |          | | | | | |
      PIPELINING                             |5.2       | |x| | | |
      SIZE                                   |5.2       |x| | | | |
      CHUNKING                               |5.2       | |x| | | |
      BINARYMIME                             |5.2       | |x| | | |
      NOTIFY                                 |5.2       |x| | | | |
                                             |          | | | | | |
  Management Protocols:                      |          | | | | | |
    Network management                       |6.1       | |x| | | |
    Monitoring queues                        |6.2       | |x| | | |
  -------------------------------------------|----------|-|-|-|-|-|-
   1.  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.
   2.  When binary transport is not available
   3.  When binary transport is available

12. Appendix - Example Voice Message

 The following message is a full-featured, all-options-enabled message
 addressed to two recipients. The message includes the sender's spoken
 name and a short speech segment.  The message is marked as important
 and private.
   To: 2145551212@vm1.mycompany.com
   To: "Parsons, Glenn, W." 2145551234@VM1.mycompany.com
   From: "Vaudreuil, Greg" 2175552345@VM2.mycompany.com
   Date: Mon, 26 Aug 93 10:20:20 CST
   MIME-Version: 1.0  (Voice 1.0)
   Content-type: Multipart/Voice-Message; Boundary = "MessageBoundary"
   Content-Transfer-Encoding: 7bit
   Message-ID: VM2.mycompany.com-123456789
   Sensitivity: Private
   Importance: High
  1. -MessageBoundary

Content-type: Audio/32KADPCM

   Content-Transfer-Encoding: Base-64

Vaudreuil Experimental [Page 20] RFC 1911 MIME Voice Profile February 1996

   glslfdslsertiflkTfpgkTportrpkTpfgTpoiTpdadasssdasddasdasd
   (This is a sample of the base-64 Spoken Name data) fgdhgd
   jrgoij3o45itj09fiuvdkjgWlakgQ93ijkpokfpgokQ90gQ5tkjpokfgW
   dlkgpokpeowrit09==
  1. -MessageBoundary

Content-type: Audio/32KADPCM

   Content-Transfer-Encoding: Base-64
   glslfdslsertiflkTfpgkTportrpkTpfgTpoiTpdadasssdasddasdasd
   (This is a sample of the base-64 Spoken Subject data) fgdhgd
   jrgoij3o45itj09fiuvdkjgWlakgQ93ijkpokfpgokQ90gQ5tkjpokfgW
   dlkgpokpeowrit09==
  1. -MessageBoundary

Content-type: Audio/32KADPCM

   Content-Transfer-Encoding: Base-64
   glslfdslsertiflkTfpgkTportrpkTpfgTpoiTpdadasssdasddasdasd
   (This is a sample of the base-64 message data) fgdhgdfwgd
   jrgoij3o45itj09fiuvdkjgWlakgQ93ijkpokfpgokQ90gQ5tkjpokfgW
   dlkgpokpeowrit09==
  1. -MessageBoundary–

13. Appendix - Audio/32KADPCM Content Type

   Mime type name: Audio
   Mime Sub-Type name: 32KADPCM
   Required Parameters: None
   Optional Parameters: None
   Encoding Considerations: Any encoding necessary for transport may be
   used.
 CCITT Recommendation G.721 [G721] describes the algorithm recommended
 for conversion of a 64 KB/s A-law or u-law PCM channel to and from a
 32 KB/s channel.  The conversion is applied to the PCM stream using
 an Adaptive Differential Pulse Code Modulation (ADPCM) transcoding
 technique.
 No header information shall be included before the audio data. When
 this subtype is present, a sample rate of 8000 Hz and a single
 channel is assumed.

Vaudreuil Experimental [Page 21] RFC 1911 MIME Voice Profile February 1996

14. Appendix - Multipart/Voice-Message

   Mime type name: Multipart
   Mime Sub-Type name: Voice-Message
   Required Parameters: Boundary
   Optional Parameters: None
   Encoding Considerations: Binary of 7 bit are sufficient.  Base-64
   and Quoted-Printable are prohibited on multipart content-types.
 The syntax of a Multipart/Voice-Message is identical to the
 Multipart/Mixed content type.  The Voice-Message content-type
 contains three body parts.  The first is an audio segment containing
 the spoken name of the originator, the second is an audio segment
 containing a spoken subject, and the third is the voice message
 itself.  Forwarded voice messages can be created by simply nesting
 multipart content types.
 The spoken name segment shall contain the name of the message sender
 in the voice of the sender.  The length of the spoken name segment
 must not exceed 12 seconds.  If no spoken name is available, the
 segment must still be present but may be empty.
 The spoken subject segment shall contain the subject of the message
 sender in the voice of the sender.  The length of the spoken subject
 segment must not exceed 20 seconds.  If no spoken subject segment is
 available, the segment must still be present but may be empty.
 The voice message body part may contain any arbitrary content
 including a multipart/mixed collections of body parts, though will
 typically be an audio segment.
 The default handling of the Multipart/Voice-Message shall be to voice
 the spoken-name segment and then the spoken-subject prior to
 displaying or voicing the remainder of the message.

Vaudreuil Experimental [Page 22]

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