WAP (Wireless Application Protocol)

Nov 20, 1998

Shunxing Chen
Department of Surveying
shunxing@cc.hut.fi

Linfeng Yang
Department of Computer Science
lyang@cc.hut.fi

Helsinki University of Technology  


Abstract

WAP --- a bridge between internet and wireless devises, which brings advanced applications and Internet content to digital cellular phones. And the establishment of this commonly accepted, industry-wide Wireless Application Protocol (WAP) promises very substantial benefits for wireless network operators, end-users and content developers of exciting new applications.


1. Overview

1.1. Introduction of WAP

WAP (Wireless Application Protocol) is a major a breakthrough that achieves universal Internet-based information access on wireless devices. It will make it possible for developers to write once for all networks worldwide. Carriers will be able to implement gateways that work with many brands of phones and all applications and content. Handset manufactures can make high volume, low cost handsets for all carriers.[2]

The purpose of the Wireless Application Protocol is to provide operators, infrastructure and terminal manufacturers, and content developers a common environment that will enable development of value-added services for mobile phones. The four founding members aim to create, together with other industry partners, a global wireless service specification to be adopted by appropriate standards bodies and will be independent of the network infrastructure system in place. All the applications of the protocol will be scaleable regardless of transport options and device types.[3]

The Wireless Application Protocol is targeted to bring advanced services and Internet content to digital cellular phones and terminals. A common standard means the potential for realizing economies of scale, encouraging cellular phone manufacturers to invest in developing compatible products, and cellular network carriers to develop new differentiated service offerings as a way attracting new subscribers. Consumers benefit through more and varied choice in advanced mobile communications applications and services.[3]

1.2. Infrastructure of WAP

WAP Infrastructure
  • WML: Wireless Markup Language - A tag-based display language providing navigational support, data input, hyperlinks, text and image presentation, and forms. A browsing language similar to Internet htm.
  • htm: Hypertext Markup Language
  • TeleVAS: Telephony Value Added Services [5]
  • 2. WAP's Objectives

    WAP recognizes that the consumer not only values the power and usefulness of the Web but also wishes to have it available while away from home or work. The concept is very simple: someone with a cell phone, pager, or PDA should be able to do limited Web surfing, for example, to check stock quotes, get restaurant information, or access bank accounts. But how can a wireless device with a small display render Web pages that are loaded with text that scrolls on and on? And who wants to wait "forever" for a huge image to be sent over the painfully slow wireless link? And how can a user follow links without a mouse? The goal of WAP is to extend the Web to handheld wireless devices by addressing and solving these difficulties.[4]

    WAP's goal is to allow a wide variety of wireless devices to access live information resources and applications. The philosophy behind WAP's approach is to utilize as few resources as possible on the handheld device and compensate for the constraints of the device by enriching the functionality of the network. This approach enables a variety of devices, from the very basic handset to a fully featured PDA or laptop PC, to access the same information and content. WAP software suppliers support:

    For available devices, the Wireless Application Protocol will be applicable to, but not limited to:
  • GSM-900, GSM-1800, GSM-1900
  • CDMA IS-95
  • TDMA IS-136
  • 3G systems - IMT-2000, UMTS, W-CDMA, Wideband IS-95
  •  

    3. WAP Architecture


     

    [6]

    WAP's architecture utilizes microbrowser technology based on Internet standards. The advantage of browser technology is that the handheld device decides how to display the information provided by the server. This allows each device to differentiate itself through its own User Interface. This architecture consumes very small resources on the handheld device in terms of ROM, RAM, and CPU, allowing even the most basic handsets to be equipped with the browser.

    Being lean on basic handsets does not sacrifice features on more capable devices such as Smartphones and PDA's. WAP's architecture allows for the inclusion of scripting, graphics and animations, as well as text in applications and content. Various input devices may be supported, such as touch screens and full keyboards and soft keys. This means that the more capable devices can take advantage of richer content and display the same applications with a User Interface which fits the characteristics of the device.[1]

    4. WAP Layers

    The WAP architecture follows the OSI layering model and consists of three major layers.

    4.1. Application Layer - WAE and WTA

    Wireless Application Environment (WAE) and Wireless Telephony Application (WTA) are the top-most layers in the WAP architecture. They are the main interfaces to the client devices and specify a markup language, a scripting language, and a telephony interface. WAE and WTA impose a few, simple and basic requirements on the client device. For example, the client device must maintain a "history list" of recently visited decks, so that the usr may navigate "backwards".

    4.2. Session Layer - WSP and WTLS

    Wireless Session Protocol (WSP) and Wireless Transport Layer Security (WTLS) are the session layer of the WAP architecture. They provide connection-based services to the application layer - WAE and WTA. Basically, a session is started, content is exchanged, and the session is later closed. Additionally, the session can be suspended and resumed. (NOTE: Although one would think that WTLS belongs in the transport layer, WAP places it in the session layer since the security context is based on WAP sessions rather than WAP transmissions.)

    4.3. Transport Layer - WTP and Bearer Service

    Wireless Transport Protocol (WTP) and bearer services are the protocol layer in the WAP architecture. They provide reliable transmission of WSP data packets between the client and server over a wireless link.[4]

    5. Content and Capabilities

    WAP provides three broad categories of functionality for content providers: content, scripting, and telephony.

    5.1. Content

    the basic display unit of WAP content is the "card". Since several cards may be required for a single application or service, WAP defines a content file as a group of cards, called a "deck". A deck has one or more cards and each card can be labeled just like name references within HTML files. When a deck is retrieved, the first card is automatically displayed.

    5.2. Scripting

    WAP also defines a scripting language, WML Script, which is similar in concept and purpose to JavaScript for HTML. WML Script is created by a content provider and is stored in its own file, separate from the WML that uses it. With WML Script, a card can execute functions that verify input fields or that convey limited state information between cards in a deck or even between decks. WML Scripts are accessed using a URL, just like WML content itself.

    5.3. Telephony

    Since it is expected that WAP will be implemented within a cell phone or other communication device, WAP has provisions for controlling the telephony aspects of these client devices. For example, a user may wish to find a local restaurant. Using a WAP cell phone, the user consults a "yellow pages" directory and finds an appropriate diner. To make a reservation, the user just "clicks" a button displayed by the WML card and the phone dials the restaurant . Obviously this is much easier than writing down the phone number, ending the WAP session, and dialing the number manually.[4]

    6. Beneficants from WAP

    END-USER:
    Mobile phones have become the dominant tools in communications and at the same time the Internet has become a de facto platform for information. By adopting a common protocol the end-user will be provided with more value-added services which are easy-to-access and easy-to-use directly from a mobile phone. Telephony oriented services will be made easier to understand and to use.

    OPERATORS:
    The operators can differentiate by launching special services, for example for banking, stock trading, directory services etc. A further differentiation is that the protocol makes it possible to tailor-make specific menus within the mobile phones, facilitating the use of the services. This customization can be made over the air.

    INDUSTRY:
    The telecommunications industry will be able to avoid over-lapping costs and investments if there is a common, open platform and tool for wireless messaging. This is one the first and an important step in the evolution of wireless data/messaging services which will increase the usage of data in wireless networks.

    APPLICATIONS AND CONTENT DEVELOPERS:
    The WAP standard will allow developers to develop once and content providers to publish once for all users across all protocols and all carriers. For the first time, developers can gain unified access to the entire global user community. This means that the unified opportunity that the Internet has provided to the wired world can now be made available to the wireless community.[7]

    7. Conclusion

    WAP signals a new era for the wireless industry. The mass-market handset is now poised to become a true information appliance, bringing a multitude of meaningful information to the masses. WAP promises to provide a unifying influence, in the best tradition of the Internet, for a global industry to flourish.[1]

    However, there are still existing some problems. The greatest obstacle that WAP faces is market acceptance. Will the consumer, with expectations built up from traditional Web surfing, accept the limited capability of WML decks? Second in line is the technical uncertainty of an unproven and untried system. Token compression looks promising on paper, but will the resultant reduction in transmission time be enough to warrant the complexity required by the compilers and interpreters in the client and server[4]. In a near future, WAP Forum members and others will finally solve all these problems. WAP will fill a new application space to web.

    # References

    References are listed in alphabetical order and numbered.

    [1]  Linder, B.,The Wireless Application Protocol (WAP) - Bringing Electronic Customer Care to cdmaOne(TM), August, 1998[referred 27.9.1998] 
    < http://www.cdg.org/blinder.html
    [2]  Unwired Planet, Inc., WAP Background, The Wireless Application Protocol, Overview, June 1, 1998[referred 26.9.1998] 
    < http://www.uplanet.com/datasheets/wapbackground_text.html
    [3]  Nokia Press Release, Architecture for Wireless Application Protocol Published on the World Wide Web, September 16, 97[referred 26.9.1998] 
    < http://www.nokia.com/news/news_htmls/nmp_970916.html
    [4]  RobertoDiaz:Homepage, Wireless Application Protocol (WAP), April 3, 1998[referred 26.9.1998] 
    < http://www.iit.edu/~diazrob/wap.html
    [5]  WAP forum, About WAP, July 20, 1998[referred 25.9.1998]
    < http://www.wapforum.org/about/index.htm
    [6]  WAP forum, Slide Presentation from the WAP Forum Press Briefing on 17 Feb 1998 held at the GSM Congress in Cannes, France, February 17, 1998 [referred 27.9.1998] 
    < http://www.wapforum.org/docs/slides2/index.htm
    [7]  Nokia Discovery Online, WAP Speed Ahead With Smart Messaging, Discovery Volume 45, 1997[referred 26.9.1998] 
    < http://www.nokia.com/discovery/vol45/wap.html

    # Further Information

    What is...WAP (Wireless Application Protocol)
    The definition of WAP
    Wireless Application Protocol Connects Smart Phones
    Information about defining the new Wireless Application Protocol
    WAP - Wireless Application Protocol
    Introduction for the ptotocol, WML, and WTA of WAP
    WAP Forum Meeting Helsinki
    Description about the development and existing problems of WAP
    Wab brings more net-power for the user
    Sonera supports WAP
    Spyglass Announces First-Ever WAP Compliant For Wireless Industry
    spyglass will create new solutions based on the WAP specification for both mobile phone browsers and the back-end servers
    Wireless Application Protocol to Boost Smart Phone Market
    Introduction to WAP
    TeamWARE To Incorporate Wireless Application Protocol
    TeamWARE declares to incorporate standards outlined by the WAP in future communications services
    WAP forum, Press Release 7 January 1998
    Ericsson, Motorola, Nokia and Unwired Planet establish Wireless Application Protocol Forum Ltd
    WAP forum, Press Release 17 February 1998
    Draft Wireless Application Protocol Specification published on the World Wide Web
    WAP forum, Press Release 8 September 1998
    WAP FORUM MOMENTUM ACCELERATES - 23 NEW COMPANIES JOIN IN FOUR MONTHS
    WAP Architecture Version 30-Apr-1998
    Wireless Application Protocol A
    WAP Architecture Version 30-Apr-1998
    Wireless Application Protocol Architecture Specification