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Network Working Group                                         E. Burger
Internet Draft                                 SnowShore Networks, Inc.
Document: draft-burger-um-reqts-00.txt                    February 2002
Category: Informational
Expires: August 2002


                Internet Unified Messaging Requirements


Status of this Memo

   This document is an Internet-Draft and is in full conformance with
   all provisions of Section 10 of RFC2026 [1].

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups. Note that
   other groups may also distribute working documents as Internet-
   Drafts. Internet-Drafts are draft documents valid for a maximum of
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   documents at any time. It is inappropriate to use Internet- Drafts
   as reference material or to cite them other than as "work in
   progress."

   The list of current Internet-Drafts can be accessed at
   http://www.ietf.org/ietf/1id-abstracts.txt

   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html.



1. Abstract

   Internet Unified Messaging brings together the body of work done in
   VPIM, FPIM, IMAPEXT, and other IETF work groups.  The goal is to
   provide a single infrastructure, mailbox, and set of interfaces for
   a user to get, respond to, and manipulate all of their messages, no
   matter what the media or source.  This document describes the
   requirements for providing such a service.

   Discussion of this and related drafts are on the UM list.  To
   subscribe, send the message "subscribe um" to
   majordomo@snowshore.com.  The public archive is at
   http://flyingfox.snowshore.com/um_archive/maillist.html.


2. Conventions used in this document

   This document refers generically to the sender of a message in the
   masculine (he/him/his) and the recipient of the message in the
   feminine (she/her/hers).  This convention is purely for convenience
   and makes no assumption about the gender of a message sender or


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   recipient.

   FORMATTING NOTE: Notes, such at this one, provide additional
   nonessential information that the reader may skip without missing
   anything essential.  The primary purpose of these non-essential
   notes is to convey information about the rationale of this document,
   or to place this document in the proper historical or evolutionary
   context.  Readers whose sole purpose is to construct a conformant
   implementation may skip such information.  However, it may be of use
   to those who wish to understand why we made certain design choices.

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED",  "MAY", and "OPTIONAL" in
   this document are to be interpreted as described in RFC-2119 [2].


3. Introduction

   Humans have had to contend with having multiple messaging systems
   for different messaging modes.  For example, I have a voice mail
   account for voice messages, a fax store-and-forward service for fax
   messages, and an e-mail account for Internet messages.

   The IETF has successfully completed a considerable body of work
   extending the highly successful non-real-time text messaging
   service, SMTP.  Extending the mail system for multimedia payloads
   with MIME enabled the transport of voice and fax.  The VPIM and IFAX
   work groups, respectively, have produced a number of RFCs that focus
   on voice mail and fax messaging and transport.  This draft examines
   the requirements for unified messaging systems.

   There has been an evolution of using Internet Mail standards [3] for
   the carriage of media-rich messages.  MIME [4] introduces the basic
   capability for transporting media-rich messages using Internet Mail.
   Then there were a number of successful efforts to use Internet Mail
   for supporting the transport of various media-specific message types
   within closed environments.  Leveraging this success, people started
   to see how to integrate the closed environments into the Internet
   Mail structure.  The ultimate goal is Unified Messaging: a single
   infrastructure, mailbox, and set of interfaces for a user to get all
   of their messages.

   The Voice Profile for Internet Mail defines a method for
   transporting voice messages between voice messaging systems using
   Internet Mail [5].  Likewise, the Extended Mode Fax [6] defines a
   method for transporting fax messages between fax messaging terminals
   using Internet Mail.

   Simple Mode Fax [7] describes how one can deliver facsimile
   documents using the Internet Mail infrastructure, including standard
   Internet Mail clients.  Said differently, the document brought
   facsimile into the Internet Mail domain.


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   Likewise, Internet Voice Mail [8] describes how one can generate and
   deliver voice messages using the Internet Mail infrastructure,
   including standard Internet Mail clients.

   With this set of developments, we are now in a position to gather
   these standards and develop new protocols where needed to deliver
   true unified messaging.


4. General Requirements

4.1. Reuse Existing Protocols

   To the extent feasible, the unified messaging framework SHOULD use
   existing protocols whenever possible.

4.2. Maintain Existing Protocol Integrity

   In meeting requirement 4.1, the unified messaging framework MUST NOT
   redefine the semantics of an existing protocol.

   Said differently, we will not break existing protocols.
4.3. Reception Context

   When the user receives a message, that message SHOULD receive the
   treatment expected by the sender.  For example, if the sender
   believes he is sending a voice message, voice message semantics
   should prevail.

4.4. Sending Context

   When the user sends a message, she SHOULD be able to specify the
   message context.  That is, whether the network should treat the
   message as an Internet Mail message, voice message, video message,
   etc.


5. Infrastructure Preservation

   A major goal for the unified messaging framework is to not change
   any existing Internet infrastructure.  For example, the behavior of
   mail transfer agents (MTAs) should not change.  Likewise, the
   behavior of existing mail clients should not change.

   Messages created in a unified messaging context MUST NOT require
   changes to existing mail clients.  However, there may be a loss in
   service in certain circumstances.

   The unified messaging framework MUST be able to handle messages
   created in a non-unified messaging context, for example, a simple,
   RFC 822 [9] text message.



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6. Voice Requirements

   The expectation of voice mail users are described in [8] and [10].
   To summarize, voice mail users have heightened expectations of
   privacy, delivery confirmation, and addressing than Internet Mail
   users.

   On the retrieval side, there are significant real-time requirements
   for retrieving a message for voice playback.  More than any other
   media type, including video, voice is extremely sensitive to
   variations in playback latency.  The unified messaging framework
   MUST address the real-time needs of voice.


7. Fax Requirements

   Fax users have a particular expectation that is a challenge for
   unified messaging.  When a person sends a fax, their expectation is
   the user has received the message upon successful transmission.
   This clearly is not the case for Internet Mail.

   OPEN ISSUE: How will we address this?


8. Video Requirements

   Video mail has one outstanding feature: Video messages are large!
   The unified messaging framework MUST scale for very large messages.


9. Security Considerations

   Security will be a very important part of unified messaging.  In
   addition to the security issues present in Internet Mail, people
   have higher expectations for Voice and Fax messaging.  The goal,
   wherever possible, is to preserve the semantics of existing
   messaging systems and meet the expectations of users with respect to
   security and reliability.


10. References


   1  Bradner, S., "The Internet Standards Process -- Revision 3", BCP
      9, RFC 2026, October 1996.

   2  Bradner, S., "Key words for use in RFCs to Indicate Requirement
      Levels", BCP 14, RFC 2119, March 1997

   3  Vaudreuil, G. and Parsons, G., "Voice Profile for Internet Mail -
      version 2", RFC 2421, September 1998



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   4  Freed, N. and Borenstein, N., "Multipurpose Internet Mail
      Extensions (MIME) Part One: Format of Internet Message Bodies",
      RFC 2045, November 1996

   5  Resnick, P. (Editor), "Internet Message Format", RFC 2822, April
      2001

   6  Masinter, L. and Wing, D., "Extended Facsimile Using Internet
      Mail", RFC 2532, March 1999

   7  Toyoda, K., Ohno, H., Murai, J., and Wing, D., "A Simple Mode of
      Facsimile Using Internet Mail", RFC 2305, March 1998

   8  McRae, S., "Internet Voice Messaging",
      draft-ietf-vpim-ivm-03.txt, work in progress

   9  Crocker, D., "Standard for the format of ARPA Internet text
      messages", RFC 822 (obsolete), August 1982

   10 Burger, E., Candell, E., Eliot, C., and Klyne, G., "Message
      Context for Internet Mail", draft-ietf-vpim-hint-07.txt, June
      2001




11. Acknowledgments

   I would like to thank Greg Vaudreuil and Glen Parsons for convincing
   me this is a worthwhile effort.


12. Author's Addresses

   Eric Burger
   SnowShore Networks, Inc.
   Chelmsford, MA
   USA

   Phone: +1 978/367-8403
   Email: eburger@snowshore.com












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