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Network Working Group                                       G. VaudreuilRequest for Comments: 1911                        Octel Network ServicesCategory: Experimental                                     February 1996Voice Profile for Internet MailStatus 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 conformantVaudreuil                     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   andRFC 1522, Multipurpose Internet Mail Extensions;RFC 1651,RFC1652, andRFC 1653, SMTP Service Extensions (ESMTP); andRFC 1034 andRFC 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 theRFC1425 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   TheRFC 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 toVaudreuil                     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 convertRFC 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 aRFC 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-bitVaudreuil                     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 aVaudreuil                     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 19965.3 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 andRFC 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",RFC1892, 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.ComVaudreuil                     Experimental                     [Page 17]

RFC 1911                   MIME Voice Profile              February 199611. 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 available12. 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     --MessageBoundary     Content-type: Audio/32KADPCM     Content-Transfer-Encoding: Base-64Vaudreuil                     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==     --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==     --MessageBoundary     Content-type: Audio/32KADPCM     Content-Transfer-Encoding: Base-64     glslfdslsertiflkTfpgkTportrpkTpfgTpoiTpdadasssdasddasdasd     (This is a sample of the base-64 message data) fgdhgdfwgd     jrgoij3o45itj09fiuvdkjgWlakgQ93ijkpokfpgokQ90gQ5tkjpokfgW     dlkgpokpeowrit09==     --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 199614.  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]