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 six months and may be updated, replaced, or obsoleted by other 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 Burger Informational - Expires August 2002 1 UM Requirements February 2002 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. Burger Informational - Expires August 2002 2 UM Requirements February 2002 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. Burger Informational - Expires August 2002 3 UM Requirements February 2002 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 Burger Informational - Expires August 2002 4 UM Requirements February 2002 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 Burger Informational - Expires August 2002 5 UM Requirements February 2002 Full Copyright Statement Copyright (C) The Internet Society (2002). 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