RFC - 2524

Neda's Efficient Mail Submission and Delivery (EMSD) Protocol Specification Version 1.3

Original:	ftp://ftp.isi.edu/in-notes/rfc2524.txt
Authors:	M. Banan [Neda Communications, Inc.]
Date:	February 1999
Category:	Informational

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Referred by:	2 RFC
Refers to:	4 RFC

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Status

This memo provides information for the Internet community. It does not specify an Internet standard of any kind. Distribution of this memo is unlimited.

Copyright Notice

Copyright (C) The Internet Society (1999). All Rights Reserved.

IESG Note

   The protocol specified in this document may be satisfactory for
   limited use in private wireless IP networks.  However, it is
   unsuitable for general-purpose message transfer or for transfer of
   messages over the public Internet, because of limitations that
   include the following:

   - Lack of congestion control

      EMSD is layered on ESRO [RFC 2188], which does not provide
      congestion control.  This makes EMSD completely unsuitable for
      end-to-end use across the public Internet.  EMSD should be
      considered for use in a wireless network only if all EMSD email
      exchanged between the wireless network and the public Internet
      will transit an EMSD<->SMTP gateway between the two regions.

   - Inadequate security

      The document specifies only clear-text passwords for
      authentication.  EMSD should be used across a wireless network
      only if sufficiently strong encryption is in use to protect the
      clear-text password.

   - Lack of character set internationalization

      EMSD has no provision for representation of characters outside of
      the ASCII repertoire or for language tags.

   - Poorly defined gatewaying to and from Internet Mail

      Because Internet Mail and EMSD have somewhat different and
      conflicting service models and different data models, mapping
      between them may provide good service only in limited cases, and
      this may cause operational problems.

   The IESG therefore recommends that EMSD deployment be limited to
   narrow circumstances, i.e., only to communicate with devices that
   have inherent limitations on the length and format of a message (no
   more than a few hundred bytes of ASCII text), using either:

   a. wireless links with adequate link-layer encryption and gatewayed
      to the public Internet, or

   b. a private IP network that is either very over-provisioned or has
      some means of congestion control.

   In the near future, the IESG may charter a working group to define an
   Internet standards-track protocol for efficient transmission of
   electronic mail messages, which will be highly compatible with
   existing Internet mail protocols, and which wil be suitable for
   operation over the global Internet, including both wireless and wired
   links.

Abstract

This document specifies the protocol and format encodings for Efficient Mail Submission and Delivery (EMSD). EMSD is a messaging protocol that is highly optimized for submission and delivery of short Internet mail messages. EMSD is designed to be a companion to existing Internet mail protocols.

This specification narrowly focuses on submission and delivery of short mail messages with a clear emphasis on efficiency. EMSD is designed specifically with wireless network (e.g., CDPD, Wireless-IP, Mobile-IP) usage in mind. EMSD is designed to be a natural enhancement to the mainstream of Internet mail protocols when efficiency in mail submission and mail delivery are important. As such, EMSD is anticipated to become an initial basis for convergence of Internet Mail and IP-based Two-Way Paging.

The reliability requirement for message submission and message delivery in EMSD are the same as existing email protocols. EMSD protocol accomplishes reliable connectionless mail submission and delivery services on top of Efficient Short Remote Operations (ESRO) protocols as specified in RFC-2188 [1].

Most existing Internet mail protocols are not efficient. Most existing Internet mail protocols are designed with simplicity and continuity with SMTP traditions as two primary requirements. EMSD is designed with efficiency as a primary requirement.

The early use of EMSD in the wireless environment is manifested as IP-based Two-Way Paging services. The efficiency of this protocol also presents significant benefits for large centrally operated Internet mail service providers.

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