rfc1911.txt

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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].



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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



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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].







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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.



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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.






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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.