Version 0.2
August 4, 2000
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This article is one of a series of articles describing various aspects of the Mobile Messaging industry and the LEAP protocols. For the complete collection of articles, see The LEAP Manifesto [2], available at http://www.LeapForum.org/LEAP/Manifesto/roadMap/index.html. The LEAP Manifesto is also available at the Free Protocols Foundation website at http://www.FreeProtocols.org/LEAP/Manifesto/roadMap/index.html.
Both The LEAP Manifesto and this article are available in multiple formats, including: HTML, PDF, PostScript, and text-only. You can view or download documents in any of these formats from the above websites.
Please note that this is a PRELIMINARY, PARTIAL DRAFT only.
This article includes sufficient useful information that we are making it available at this point; however, please bear in mind that the article may have missing pieces, organizational inconsistencies, or other rough edges.
The article is undergoing active development, and a complete, well-organized draft will be available shortly.
Interpersonal messaging is the most important and proven value proposition of the wireless medium. Existing Internet e-mail protocols have built-in assumptions, which makes them sub-optimal for use over wireless networks. The EMSD protocol fills this gap, allowing fully open, extensible (MIME) Internet e-mail connectivity over wireless networks.
Given that the fundamental components outlined above (Palm OS, CDPD, EMSD) are real products and technologies, integrating them to create an end-user product is within reach. If the integration is performed properly, the availability of wireless E-mail capability can become straight forward for the end users of this system. Any Palm Pilot user can purchase a "mobile e-mail kit", which includes a CDPD modem, CDPD account activation and the necessary software add-ons to add the EMSD capability to the palmtop. In fact, there are several channel models which can be used to deliver the wireless messaging capability to the end user, so forming a "mobile e-mail kit" is just one of them. This paper focuses on the technical issues of the integration effort at hand as opposed to marketing and channels issues. A WinCE based EMSD/CDPD wireless messaging solution, when coupled with the back-end EMSD Message Transfer Agent (MTA) offers a strong value proposition with minimal infrastructure. The EMSD MTA can be running at a central server at the CDPD Network Operator site (example mail address: john.doe@emsd.cdpdProvider.net) or as a Customer Premise Equipment (CPE) at the Internet ISP or IS Department of an Organization (example mail address: john.doe@emsd.boeing.com).
This paper is available in many formats. You may wish to obtain a copy of this document in a more appropriate format before proceeding further.
This paper is one of a series of white papers that introduces the "world" of Efficient Mail Submission & Delivery (EMSD).
If you are not familiar with EMSD General, you may wish to read the "Introduction to EMSD - White Paper" [1].
In the context of this paper, any wireless, IP based network. Several networks such as the pACT network under development by AT&T Wireless Services, as well as the widely deployed CDPD network fit this description. Also applicable are a number of other proprietary wireless networks which expose an IP interface, such as Ricochet wireless IP network from Metricom, Inc.
CDPD is a wireless, mobile two-way data network offering coverage footprint equivalent to cellular voice in many markets. CDPD exposes an IP interface and a fixed, "real" IP address to each subscriber node (End System) as assigned by the CDPD Network Service Provider at the time of end user provisioning. CDPD mobile nodes enjoy full mobile connectivity using the same IP address throughout the entire CDPD national coverage area due to inherent support of mobility built into CDPD.
EMSD is an open, extensible and efficient message submission and delivery protocol designed specifically for the wireless network. It minimizes the network traffic required to send and receive messages, thus producing a messaging protocol that meets the needs of the mobile communicator. Fewer and smaller packets means extended battery life, efficient use of carrier bandwidth and support for marginal coverage areas. EMSD is an open specification that is an extension of the existing messaging world.
EMSD is up to 5 times more efficient than SMTP both in terms of the number of packets transmitted and in terms of number of bytes transmitted (see Efficiency Study of EMSD vs. SMTP/POP3/IMAP (PDF <61 KB)> (Postscript <165 KB>)
EMSD protocols are openly available through online RFC Library (ftp://ftp.isi.edu/in-notes/rfc2524.txt)
As with other open standards like SMTP, POP, etc., multiple implementations of EMSD are available and various development tools and products are emerging. Being the premier developer of the EMSD Protocols and Implementations, Neda Communications, Inc. offers several products for the mobile device manufacturers, network operators and corporate IS organizations.
In Table 1, the number of "X"es in each box denote to what extent a particular function is supported by a particular protocol.
It is important to note that the scope of EMSD protocols was deliberately limited to the primary requirement for mobile messaging which is: "submission and delivery of time critical important messages". EMSD is designed to complement existing mailbox access protocols such as IMAP.
Although there are proprietary implementations of messaging protocols offered by various vendor over various wireless networks, EMSD is the only open efficient messaging protocol available. The openness of EMSD is a key attribute to help expand the wireless messaging, just as SMTP and POP helped to establish and expand the (now large) Internet E-mail industry years ago.
Integrating true Internet e-mail connectivity to the Palm OS platform using EMSD over CDPD is very feasible and is a natural fit to the WinCE's "Companion" model.