Model
Version 1.2
March 1, 2001
This document describes the Lightweight & Efficient Application Protocols (LEAP), a set of protocols for mobile and wireless applications.
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Model
Until now, the Internet has been largely based upon simple protocols. However, the era of simple protocols is now over. The new Internet reality is that of wireless networks, providing service to legions of miniaturized, hand-held mobile devices. This reality places an entirely new set of requirements on the underlying communications protocols: they must now provide the power efficiency demanded by hand-held wireless devices, together with the bandwidth efficiency demanded by wide area wireless networks.
It is now time for a new generation of protocols to be implemented, designed to address the need for performance, rather than simplicity.
The industry-wide adoption of this new generation of powerful and efficient protocols will have enormous consequences. Protocols addressing the correct requirements will become the lynchpin of a huge new industry. The stakes are enormous, and ferocious competition is to be expected within all segments of the industry. All manner of wild claims and misrepresentations are also to be expected. At the time of writing, the main claimant to the protocol throne is the Wireless Applications Protocol, or WAP. However, WAP will eventually prove to be entirely inadequate to the role being claimed for it.
We have designed a set of protocols, the Lightweight & Efficient Application Protocols, or LEAP, which we believe is destined to displace WAP and become the de facto industry standard. These protocols, published as Internet RFC 2524 and RFC 2188, are designed to address all the technical requirements of the industry, and are oriented towards providing the greatest benefit to the industry and the consumer.
This manifesto is about our vision of the future of the Mobile and Wireless Applications Industry. In the remainder of the manifesto we present the details of our vision, and we justify our claims. We justify our assertion that the industry needs a new generation of protocols, we explain why our protocols fulfil this need, and we describe how and why these protocols will achieve dominance.
The protocols are free, open and in place. Open-source software implementations of the protocols are available for all major platforms. The combination of free protocols and open-source software ensures acceptance of the protocols in the Internet mainstream. There can be no stopping this.
Most of our discussion throughout this Manifesto is framed in terms of a particular technology, namely, Mobile Messaging. It is important to bear in mind, however, that Mobile Messaging is just one aspect of a broader technology: Mobile Consumer Data Communications. Mobile Consumer Data Communications refers to the general ability of an end-user to send and receive digital data at a hand-held device via a wireless network. This technology includes Mobile Messaging as a special case, but also includes other wireless data transfer capabilities such as general Internet access, web browsing, etc.
Much of the discussion set forth in this Manifesto applies with equal force to all mobile data communications applications, not just that of messaging. However, it is currently well understood that the dominant application for mobile data communications is, in fact, Mobile Messaging, not web browsing or other Internet applications. Therefore throughout this Manifesto we will focus our attention on the messaging application.
Though our discussion will be framed in terms of Mobile Messaging, the reader should bear in mind that the same principles apply to all forms of mobile data communications.
Also, whenever we speak of the Mobile Messaging industry, we are referring to the totality of what is required to accomplish effective mobile messaging capabilities for the end user.
We are not referring to the implementation of mobile messaging on any particular device, such as a mobile phone, PDA, palmtop PC, laptop PC, or two-way pager. Similarly, we are not restricting our focus to any specific technologies or standards, nor are we restricting our focus to a specific market or set of subscriber services.
Rather, we are referring to the entire set of technologies and constituencies which are required to enable Mobile Messaging. This includes: mobile handheld devices and their manufacturers, wireless modems and their manufacturers, wireless data networks and their operators, ISPs and other service providers, and the set of protocols and software implementations required to allow interplay and cooperation among these various consituencies.
Our purpose in writing this Manifesto is very ambitious: we wish to describe our vision of all that is required to build the entire Mobile Messaging industry.
Engineering is the art of making intelligent trade-offs between conflicting requirements. A perennial engineering trade-off is that which must be made between the need for simplicity, and the need for performance. In the case of wireless data communications, performance means such things as data transfer speed, power efficiency, and bandwidth efficiency.
The 1980s and 1990s were the decades of simple protocols - protocols such as the very aptly named Simple Mail Transfer Protocol (SMTP), and Simple Network Management Protocol (SNMP). A great deal of the success of these and other Internet protocols can be attributed to their simplicity.
The first generation of network engineers and network operators were only able to view network communications in relatively simple terms. It was appropriate to cater to that simplicity with simple protocols. A key reason for the success of these early protocols is the lack of technical sophistication on the part of first-generation network engineers and operators.
Simple protocols are easier to make widespread than ``good'' protocols (meaning those which have better capabilities and performance), for the basic reason that network engineers and operators are able to adopt and implement simple protocols much more easily than ``good'' protocols.
However, things have changed. Network communications has now expanded dramatically and forcefully into the wireless and mobile data communications arena, and wireless applications demand efficiency. The move to wide-area wireless has significantly shifted the location of the ideal engineering balance between simplicity and performance - moving it away from simplicity, and towards performance.
We therefore need a new generation of high-performance, efficient protocols, to cater to the demands of wireless applications. The point is sometimes made that the need for efficiency in the wireless arena is a temporary one - that advances in wireless engineering technology in the form of third generation (3G) systems will eliminate existing bandwidth limitations, obviating the need for efficient protocols. As long as the capacity of wireless networks remains finite, however, the need for efficiency will persist. Efficient usage is an inherent requirement for any finite resource, therefore the requirement for efficient bandwidth usage and battery longevity is permanent.
Where will the required protocols come from? Traditionally, industry-wide protocols have their origins in one of two sources:
Unfortunately, neither of these groups has produced a set of protocols which meets the industry's needs. The first group above, represented by a set of telephone companies, has generated the WAP specification. However, as we will argue in detail later, this specification is grossy unfit for its claimed purpose. Among other things it is poorly designed, not the product of open peer review, and crippled with Intellectual Property Right (IPR) restrictions. It is essentially a business construct, not an engineering one. In the long run WAP cannot possibly survive as a viable solution. In the short run it can only have a destructive effect on the wireless industry.
The second group above, most notably represented by IETF, has likewise failed to produce an acceptable standard. IETF represents the tradition of simple protocols, a tradition which wireless communications has made obsolete. Unfortunately, IETF remains rooted in this tradition, and has not adapted to the new realities of wireless communications. Until it does so, IETF will remain ineffective as a protocols and standards body. In the area of efficient protocols, IETF is simply bankrupt.
Fortunately, there are other sources of innovation. One of these is the radical new development that comes out of nowhere, taking everybody by surprise. Typically this originates in the actions of a small group of independent experts, with a deep understanding of the technology and industry, and who are passionate about and committed to its health and vigor.
Note that the World Wide Web itself originated in neither of the traditional sources, but instead came from an entirely different and unexpected direction: a group of physicists at the CERN laboratory in Switzerland. As another example, Pretty Good Privacy (PGP), now the de facto standard for electronic data encryption, also came from neither traditional source. It was essentially the creation of a single man: Phil Zimmermann. Armed with a vision and a belief in its value, Zimmermann single-handedly made PGP the dominant consumer encryption application - displacing the IETF alternatives in the process.
The solution to the current wireless application dilemma is also likely to come from an unexpected source - and we believe that we are that source. In the world of the Internet, we have learned to expect the unexpected.
We have developed a set of protocols which we believe address all aspects of the industry's needs. Beyond their purely technical requirements, a fundamental requirement of all industry-building protocols is that they be completely open and free from patents and other IPR restrictions - either because no patents actually exist, or because reasonably non-restrictive licenses are granted by the patent holder. In the rest of this document, this is what we mean when we speak of ``patent-free'' protocols.
The presence of patented components within a protocol is extremely undesirable, since this undermines the ultimate purpose of the protocol: its unrestricted adoption and usage. The process that we have followed in developing our protocols has been such as to ensure that they are entirely open and, as far as this can be guaranteed, patent-free. A significant part of this process consists of our full committment to the processes and procedures of the Free Protocols Foundation (FPF).
The FPF is an organizational framework for the development and maintenance of free protocols. It allows developers to declare publicly that the protocols they have developed are intended to be patent-free, and that it is their intention to keep them patent-free into perpetuity. We have made this declaration through the Free Protocols Foundation with regard to our own protocols.
Note that this is in sharp contrast to the WAP protocols, which include severe IPR restrictions. This creates an unfair market advantage in favor of the initial WAP designers. Our intention is to create a protocol which does not favor any one industry player over another, and places competition where it belongs: on the merits of each company's individual products and services.
We have created the general framework for a set of high-performance, efficient protocols which are ideal for mobile and wireless applications. We refer to this general framework as the Lightweight & Efficient Application Protocols (LEAP).
The need for efficient protocols extends across all aspects of wireless data communications, including e-mail, web browsing, and other applications. The LEAP architecture accommodates all of these applications. Our initial implementation, however, is focussed on the Mobile Messaging application, since we believe that this is the dominant application for wide-area wireless networks.
All efficient applications have the requirement for an efficient transport mechanism. For this reason, the initial focus of our protocol development effort has been on creating a general efficient transport mechanism. The resulting protocol is referred to as Efficient Short Remote Operations (ESRO). ESRO is a reliable, connectionless transport mechanism, forming the foundation for the development of efficient protocols when TCP is too much and UDP is too little.
Our Efficient Mail Submission and Delivery (EMSD) protocol is built on top of ESRO, and is designed to address the Mobile Messaging application.
Both of these protocols have been published as Internet RFCs: ESRO as RFC 2188, and EMSD as RFC 2524. RFC publication ensures that the protocols are freely, easily and permanently accessible to anyone who wishes to use them.
Note that this also is in stark contrast to WAP, which is self-published by the members-only WAP Forum. Furthermore, the WAP Forum reserves the right to make unilateral changes to its protocols; each of the WAP protocols carries on its cover page the disclaimer, ``subject to change without notice.''
Publication of a protocol as an Internet RFC ensures that the protocol will remain stable and permanently available to anyone who wishes to use it, and for this reason is the mainstream Internet publishing method. The declining of the WAP Forum to publish their specifications as Internet RFCs suggests either that the forum wishes to retain an inappropriate degree of control over the specifications, or that the specifications do not meet the minimum technical standards required for RFC publication.
LEAP originated in 1994 as part of the research and development initiatives of McCaw Cellular's wireless data group (now AT&T Wireless Services). The development work that would eventually lead to LEAP was initially undertaken in the context of the CDPD network; its scope was later expanded to include the Narrowband PCS network also.
By 1996 McCaw Cellular was fully committed to paging, had recently purchased two nationwide narrowband wireless PCS licenses, and wished to develop an efficient wireless message transport and delivery system. Neda Communications, Inc., an independent consulting company working under contract to McCaw Cellular, played a significant role in the development of the required system. Neda Communications had also been involved from the outset in the development of the CDPD specification.
In 1997 however, soon after the purchase of McCaw Cellular by AT&T, the latter company abandoned narrowband PCS paging altogether. Prior to this event, Neda Communications had secured from AT&T the necessary rights to continue independent development of the protocols. Therefore, recognizing the eventual future need for these protocols, Neda then undertook to continue development of the protocols independently of AT&T. They were eventually completed by Neda, published as RFCs, and now form the cornerstone of the LEAP protocols.
Our ultimate goal is to make these protocols widespread. Developing and publishing a set of protocols, however, is just the beginning. Protocols become accepted as standards as a result of public review, modification by consensus, and ultimately by standing the test of usage in the industry at large.
To provide a forum for these processes, we have created EMSD.org and ESRO.org. Each of these organizations allows public review of the respective protocol, and provides a mechanism for correction and enhancement of the protocol as a result of collective experience. Any interested person can become a member of these organizations and participate in the further development of the protocols. The only requirement for membership is that participants must adhere to the principles and procedures of the Free Protocols Foundation, ensuring that the protocols remain permanently patent-free.
Note that this also is in sharp contrast to WAP. Participation in WAP, far from being open and public, requires a $27,000 membership fee (as of February 2000), and takes place entirely behind closed doors.
In order for the protocols to become widely accepted, they must be implemented in the form of software solutions that are readily available for deployment by end-users. We have therefore created open-source software implementations of the protocols for most common platforms. Protocol engines are available in the form of portable code which has been ported to a variety of platforms. On the device side, software is available for Windows CE, Palm OS, EPOC, and others. On the message center side, software is available for NT, Solaris, and Linux.
As noted above, our initial emphasis is on the Mobile Messaging application. Protocol engines are only a single component of a larger picture; in order to provide complete solutions to the user it is necessary to integrate these protocols into other existing pieces of software. To that end we have created MailMeAnywhere.org, where fully-integrated solutions in open-source format are made available to the user.
We will initially ``prime the pump'' by providing free subscriber services through ByName.net and ByNumber.net. This will provide initial support for adoption of the protocols by end-user devices. Usage of the protocols among a sufficient number of user devices will then provide the motivation for usage among the message center systems.
All the components that are needed to accomplish these goals are complete, in place, and ready to go. These components are:
http://www.esro.org
and
http://www.emsd.org
Collectively, the above components represent a complete recipe for the success of the LEAP protocols. All the pieces of the puzzle are complete, and there are no missing pieces.
As noted above, the LEAP protocols are entirely open, and any interested person or organization may participate in their development. To participate in the development of the LEAP protocols in general, visit the LEAP Forum website at http://www.leapforum.org/. To participate in the development of specific members of the LEAP family of protocols, visit the ESRO.org website at http://www.esro.org/, or the EMSD.org website at http://www.emsd.org/.
All of the above websites host mailing lists for commentary and general information exchange regarding the protocols. In particular, ESRO.org and EMSD.org host Working Group mailing lists for active development of their respective protocols.
In addition, we invite participation in the development of The LEAP Manifesto itself. We expect that as the LEAP family of protocols grows and becomes implemented on additional platforms, additional articles will be included in the Manifesto. Any person or organization may submit information or articles that they feel are appropriate for inclusion in the Manifesto; any such material will be given due consideration by the Manifesto editor.
In addition, we would welcome the translation of key Manifesto articles into foreign languages. One such translation has already taken place; the Manifesto article The WAP Trap is now available in French under the title Le WAP a la Trappe. Other key articles that would be greatly desirable in foreign language translations include LEAP: One Alternative to WAP, and Operation WhiteBerry. Persons interested in writing foreign language translations are asked to contact the Manifesto editor at info@leapforum.org.
We also invite general commentary and criticism of the Manifesto. Please let us know of any errors, omissions or ambiguities you may find in the Manifesto. Any input or commentary should be submitted to the Manifesto editor at info@leapforum.org.
Throughout the Manifesto, we frequently refer to ourselves in the first person, and we also refer to several organizations and domains that are in some way related to the LEAP protocols. The question may be asked, who exactly are ``we''? Who are the authors of the Manifesto, and what is their relationship to the organizations involved in the development of LEAP? Who owns LEAP? In this section we provide the answers to these questions.
Mr. Banan is also the president of Neda Communications, Inc. He is also the president and a board member of the Free Protocols Foundation.
Neda has independently led the development of the LEAP protocol specifications since 1997. Neda has also developed a comprehensive set of software implementations of the LEAP protocols, which it intends to subject to the GNU Public License and make freely available.
No one owns the LEAP protocols. The protocol specifications reside entirely in the public domain.
For more information, visit the LEAP Forum website at http://www.leapforum.org/.
Both organizations maintain several mailing lists, to which any interested person or organization may subscribe. The ESRO and EMSD websites and mailing lists are presently hosted by Neda equipment and network resources, and managed by Neda personnel.
In particular, each organization hosts a Working Group mailing list for active development of the corresponding protocol. Mohsen Banan is the current chairperson of both Working Groups, with responsibility for coordinating the Working Group development effort.
For complete information, visit the
appropriate website at either
http://www.esro.org/
or
http://www.emsd.org/.
For more information see the Free Protocols Foundation website at http://www.FreeProtocols.org.
The purpose of The LEAP Manifesto is to provide a complete description of the LEAP protocols and their intended role in the development of the Mobile Messaging industry. The Manifesto includes:
The LEAP Manifesto is organized as a series of largely independent articles. Each of these articles stands on its own, and can be read and understood independently of the others. Together, these articles provide a complete picture of the Mobile Messaging industry and the role of the LEAP protocols. Since each article is intended to be self-contained, some material is duplicated in more than one article.
The LEAP Manifesto consists of the following articles:
The LEAP Manifesto is a work in progress, and various additional articles are planned for future inclusion in the Manifesto.
Some of these future articles already exist in draft form, and are available for review in the Draft Documents section of the LEAP Forum website at http://www.leapforum.org/draft-leapManifesto/. As these and other articles are completed, they will be incorporated into the Manifesto.
The LEAP Manifesto and all of its component articles are available in multiple formats, including HTML, PDF, PostScript, and plain text. You can view or download the Manifesto in any of these formats from the LEAP Forum website at http://www.LeapForum.org/leap/index.html. The LEAP Manifesto is also available at the Free Protocols Foundation website at http://www.FreeProtocols.org/leap/index.html.
The key component of the Manifesto is a set of mobile messaging protocols called the Lightweight & Efficient Application Protocols, or LEAP. LEAP is a set of high-performance, efficient protocols which are ideal for mobile and wireless applications. This article provides a brief overview of the LEAP protocols; complete details are provided elsewhere in The LEAP Manifesto [65].
Engineering is the art of making intelligent trade-offs between conflicting requirements. A perennial engineering trade-off is that which must be made between the need for simplicity, and the need for performance. In the case of wireless data communications, performance means such things as data transfer speed, power efficiency, and bandwidth efficiency.
The 1980s and 1990s were the decades of simple protocols - protocols such as the very aptly named Simple Mail Transfer Protocol (SMTP), and Simple Network Management Protocol (SNMP). A great deal of the success of these and other Internet protocols can be attributed to their simplicity.
The first generation of network engineers and network operators were only able to view network communications in relatively simple terms. It was appropriate to cater to that simplicity with simple protocols. A key reason for the success of these early protocols is the lack of technical sophistication on the part of first-generation network engineers and operators.
Simple protocols are easier to make widespread than ``good'' protocols (meaning those which have better capabilities and performance), for the basic reason that network engineers and operators are able to adopt and implement simple protocols much more easily than ``good'' protocols.
However, things have changed. Network communications has now expanded into the wireless and mobile data communications arena, and wireless applications demand efficiency. The move to wide-area wireless has significantly shifted the location of the ideal engineering balance between simplicity and performance - moving it away from simplicity, and towards performance.
Wireless networks are constrained by bandwidth limitations, and the hand-held devices they serve are constrained by limitations such as display size, battery capacity, and memory capacity. These constraints place an extremely high premium on the efficiency of data transfer.
Existing Internet protocols do not provide the required efficiency. We therefore need a new generation of high-performance, efficient protocols, to cater to the demands of wireless applications. The point is sometimes made that the need for efficiency in the wireless arena is a temporary one - that advances in wireless engineering technology in the form of third generation (3G) systems will eliminate existing bandwidth limitations, obviating the need for efficient protocols. As long as the capacity of wireless networks remains finite, however, the need for efficiency will persist. Efficient usage is an inherent requirement for any finite resource, therefore the requirement for efficient bandwidth usage and battery longevity will remain.
The LEAP protocols are intended to be an enabling catalyst for the growth of the wireless-IP based Mobile Messaging industry, and have been designed with this goal in mind from the outset. They have been designed as a genuine enabling technology which will bring enormous benefits to the industry and the consumer. They are a sound engineering construction based on true openness and patent-freedom.
The LEAP protocols a general-purpose solution to the problem of efficient message transfer, and their use is not limited to any particular device type or network. In particular, LEAP is compatible with all wireless-IP networks. Examples of wireless networks which provide native support for LEAP are CDPD, GSM, packet CDMA, and PCS.
The basic organization of the LEAP protocols is shown in Figure 2.1.
As shown in Figure 2.1, the LEAP protocols are layered. The lower layer is called Efficient Short Remote Operations, or ESRO. The ESRO layer provides reliable connectionless transport services which can be used for a variety of applications. For example, in addition to mobile messaging services, ESRO can also be used as a transport service for credit card verification applications and efficient micro browsers.
For more information on ESRO see the article ESRO: A Foundation for the Development of Efficient Protocols within The LEAP Manifesto, or visit the ESRO website at http://www.esro.org/.
One of the efficient application layers built on top of ESRO is called Efficient Mail Submission & Delivery, or EMSD. EMSD is the component of LEAP that addresses the Mobile Messaging application.
EMSD is a specialized native Internet messaging protocol. It defines a similar set of services to the existing SMTP protocols. It defines a complete set of rules for message submission (end-user device to server) and message delivery (server to end-user device). EMSD meets or exceeds the level of functionality, reliability and security provided by the existing SMTP protocols.
Though its use is not limited to wireless networks, EMSD has been designed specifically to address the requirements of wireless networks, such as CDPD, Wireless-IP, Mobile-IP. In particular, EMSD has been designed with a very strong and clear emphasis on efficiency.
EMSD is highly optimized for the submission and delivery of short (typically 4 kilobytes or less) Internet e-mail messages, and is therefore extremely well suited to the wireless environment. EMSD improves on existing messaging protocols by optimizing the exchange between the server and the end-user device, both in terms of the number of bytes transferred and the number of transmissions. Because of the required timeliness of the messages, mailbox access protocols like POP and IMAP are not used. EMSD is the only truly open messaging protocol that is specifically designed for the wireless network environment.
EMSD is a natural extension of the existing Internet e-mail environment, and accommodates the two-way paging model of usage, in which time-critical messages are "pushed" to the recipient.
Any network or network operator which faces significant bandwidth and capacity limitations can benefit from the use of EMSD. Any user of a network who must bear high costs for measured network usage can benefit from the use of EMSD.
The initial use of EMSD is expected to be primarily to provide Mobile Messaging services over IP-based wireless networks. However, EMSD can also function as an adjunct to Mail Access Protocols for "Mail Notification Services."
For more information on EMSD see the article EMSD: The LEAP E-Mail Component within The LEAP Manifesto, or visit the EMSD website at http://www.emsd.org/.
The Efficient Hyper Text Delivery (EHTD) layer is a hypertext transfer protocol which is optimized for the efficient transfer of short markup pages. EHTD is the component of the LEAP protocols which facilitates web browsing. Along with EMSD, EHTD also benefits from the reliable efficient services of ESRO. A multiplicity of efficient markup languages can be used in conjunction with EHTD. Development of the EHTD protocol is currently in progress.
Various other efficient application protocols are either under development, or anticipated for future development. One of these is the Efficient Dictionary protocol, or E-DICT, which will enable efficient access to dictionaries and other look-up data structures. A starting point for the E-DICT protocol is currently being created. In developing E-DICT, we intend to build on the existing work already done in the context of the DICT protocol.
We anticipate that additional protocols will be needed for a variety of future applications, not all of which can be foreseen at this time. These applications will include such things as efficient implementations of ESRO-based instant messaging, chat, white pages, and others.
All LEAP protocols are designed with efficiency in mind. In this section we describe the efficiency characteristics of EMSD, the LEAP e-mail protocol. Other LEAP protocols deliver similar efficiency benefits.
Most existing Internet e-mail protocols are designed with simplicity, and continuity with SMTP traditions, as two of the primary design requirements. These requirements are in conflict with efficiency of data transfer, and for this reason most existing Internet e-mail protocols are not efficient.
EMSD, on the other hand, has been designed with efficiency as its primary requirement. For this reason, EMSD is a great deal more efficient than existing Internet e-mail protocols.
A detailed efficiency study of the LEAP protocols is provided in the article entitled Efficiency of EMSD [57] within The LEAP Manifesto. That article presents various efficiency studies which compare the efficiency of EMSD to other e-mail protocols such as SMTP, POP and IMAP, and which demonstrate the efficiency advantages of EMSD.
In this section we provide a brief summary of EMSD's efficiency characteristics. A comparison of the efficiency of the EMSD protocol to other messaging protocols is provided in Figure 7.3, which shows the delivery traffic overhead for EMSD and three other e-mail protocols: SMTP, IMAP and POP.
By minimizing the network traffic required to send and receive messages, EMSD meets the needs of the mobile communicator. The extreme efficiency of the EMSD protocol translates into bandwidth efficiency, which in turn translates into:
An illustration of how LEAP works is shown in Figure 21.4. As the figure shows, LEAP provides complete openness of interoperability among Mobile Messaging devices, message centers, and wireless networks.
In order to achieve this convergence, it is not sufficient for the Mobile Messaging industry merely to adopt a set of common protocols. Many would claim that WAP is in fact just such a set of common protocols. However, a further essential attribute of the required protocols is that they must be a truly integral, ``end-to-end'' part of the Internet, as opposed to ``gateways'' which accommodate unnecessary gatekeepers and middlemen.
LEAP is based on the concept of the Internet end-to-end model, in which direct communication between the client and the server assumes that the role of the network service provider is merely that of a pipe - i.e. a passive communication conduit. The Internet end-to-end model assumes that both ends are under the control and choice of the user, and that the servers are widespread, from a variety of providers, and under no specific administration or control. The Internet end-to-end model is in sharp contrast to the traditional phone company and telecommunications approach, which inserts gateways between the two ends, and creates control and exploitation opportunities for the telecommunication operators.
Bearing in mind that the natural convergence of all wireless networks to IP at Layer 3 is well under way and rapidly progressing, the key remaining requirements are: efficiency, lightweightness, miniaturization, and conformance to the Internet end-to-end model. LEAP fulfils all of these requirements. By serving as the necessary missing link, LEAP will become the ultimate basis for convergence.
The mobile e-mail component of LEAP is EMSD. In the spirit of the Internet end-to-end model, the EMSD protocol will facilitate the convergence of the IP-based two-way paging industry, and Internet e-mail, in a natural and transparent manner.
The entire LEAP family of protocols bring efficiency and functionality benefits to the user of miniaturized mobile devices. In this section we describe the user's experience of an EMSD-enabled device.
Mobile users may not always have the benefit of a wired connection, because of their frequent mobility. They may have a permanent computing system elsewhere, at which they can review large messages at their leisure (for example, messages containing Word documents, Excel spreadsheets, images, etc.). While on the move, however, they need to be kept apprised of important information that requires their immediate attention. Such information cannot wait for them to find the time to set up a laptop and dial in to check for messages. They must be able to accept messages immediately, at any time, and on a device that they can carry anywhere.
The experience of the end-user in using LEAP-based Mobile Messaging technology is illustrated in Figure 13.2.
Anyone with access to the Internet can now send a message to this user. The EMSD Service Provider accepts the message from the Internet e-mail system via standard Internet protocols, then delivers the message to the user's device via EMSD protocols. Since the modem is always on, the message can be accepted at any time, and the user can be notified immediately (in any of the ways commonly used for pager notification) that a message has arrived. The user will then activate the EMSD device and read the message.
To send a message the user enters the message, then submits it to the EMSD Service Provider via the EMSD protocols. The Service Provider then acts like a standard Internet Service Provider and sends the message to its destination.
The end-user device may have a limited display area and a limited keyboard. This is very much the case for today's cell phones, for example. If so, both the end-user and his/her correspondents may wish to make use of canned messages to facilitate their communication. These canned messages may be defined by the system or end-user device, or they may defined by the message originator as embedded multiple-choice responses.
Figure 13.2 illustrates how the Mobile Messaging needs of a typical user (we'll call him Joe) are provided by the LEAP technology. This figure includes all the required technological components, and shows how they interoperate to satisfy Joe's needs. The figure includes three major components:
If Joe receives a generic (i.e. non-LEAP) e-mail message over the Internet, then this will be fielded by his Subscriber Service provider, then forwarded to Joe's mobile device using the LEAP protocols.
Meanwhile, e-mails for Joe may be received in either his home or office mailbox systems. Joe may configure either of these systems to forward certain e-mails to his mobile device on a selective basis. If so, the qualifying e-mails will be forwarded to him directly over the Internet, using the LEAP protocols. The Subscriber Services system need not be involved in the transmission of these forwarded e-mails, since they are being sent from one LEAP-enabled system to another.
In summary, the end-user experience described above represents a superset of the capabilities of the RIM BlackBerry [tm] system. The market success of BlackBerry clearly demonstrates the large user demand for this kind of service. By providing the same functionality of BlackBerry in a completely open fashion, the benefits to the consumer will be that much greater. For further discussion, see the article Operation WhiteBerry in The LEAP Manifesto.
The LEAP protocols are intended to be open in the fullest sense of the word; they are intended to be freely and permanently available, subject to public review and revision, and without usage restrictions of any kind. Therefore the processes and procedures used throughout the development and maintenance of the LEAP protocols have been such as to endow them with these characteristics, and to ensure their integrity as public protocols.
A detailed description of the LEAP development process is provided in the article entitled The LEAP Protocol Development Model within The LEAP Manifesto. In the following sections we provide a brief summary of the major development principles.
The development and maintenance of the LEAP protocols conforms fully to the policies and procedures of the Free Protocols Foundation. In particular, Neda has declared to the Free Protocols Foundation that the LEAP protocols are patent-free to the best of its knowledge, and that it intends to keep them patent-free permanently. For more information see http://www.FreeProtocols.org.
Both protocols have been published as Internet RFCs; ESRO in September 1997 as RFC-2188 [91], and EMSD in March 1999 as RFC-2524 [5]. RFC publication is the mainstream Internet publishing procedure, ensuring that the protocols are freely, easily and permanently accessible to anyone who wishes to use them.
To provide an open forum for the continued development and maintenance of the LEAP protocols, Neda has established a public organization for each protocol.
The ESRO and EMSD protocols are maintained, respectively, by ESRO.org at http://www.esro.org/, and by EMSD.org at http://www.emsd.org/.
Each of these organizations allows public review of the respective protocol, and provides mechanisms for enhancement of the protocol as a result of collective experience.
Any interested person may participate in the further development of the protocols. Participation in the development process is entirely open and non-exclusive; there are no membership fees.
A set of specifications called the Wireless Application Protocol, or WAP, exists already, and purports to do the same things that LEAP does. However, the WAP specifications are entirely unfit for their claimed purpose, and are doomed to technological and political failure. A detailed criticism of WAP and justification of these statements is provided in an article called The WAP Trap [66] within The LEAP Manifesto.
LEAP is an alternative to WAP, that does in fact what WAP does only in fiction. For a point-by-point comparison of LEAP to WAP, see the article entitled LEAP: One Alternative to WAP [64] within The LEAP Manifesto.
Those characteristics of WAP that make it wholly unfit to be the industry standard are summarized in Table 11.1, along with the corresponding characteristics of the LEAP protocols.
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LEAP originated in 1994 as part of the research and development initiatives of McCaw Cellular's wireless data group (now AT&T Wireless Services). The development work that would eventually lead to LEAP was initially undertaken in the context of the CDPD network; its scope was later expanded to include the Narrowband PCS network also.
By 1996 McCaw Cellular was fully committed to paging, had recently purchased two nationwide narrowband wireless PCS licenses, and wished to develop an efficient wireless message transport and delivery system. Neda Communications, Inc., an independent consulting company working under contract to McCaw Cellular, played a significant role in the development of the required system. Neda Communications had also been involved from the outset in the development of the CDPD specification.
In 1997 however, soon after the purchase of McCaw Cellular by AT&T Wireless, the latter company abandoned the wireless messaging project. Prior to this event, Neda had secured from AT&T the necessary rights to continue independent development of the protocols. Therefore, recognizing the eventual future need for these protocols, Neda then undertook to continue development of them independently of AT&T. They were eventually completed by Neda, published as RFCs, and now form the basis of the LEAP protocols.
Prior to abandoning wireless messaging, AT&T Wireless Services invested several million dollars in related development work. In creating LEAP, therefore, Neda was able to build upon a large abandoned investment by AT&T Wireless.
Protocols come in all shapes and sizes, and from a variety of sources. Some are proprietary, intended for use exclusively by their developer. Others
