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5

Protocols for wireless applications

Wireless data networks present a more constrained communication environment compared

to wired networks. Because of fundamental limitations of power, available spectrum, and

mobility, wireless data networks tend to have less bandwidth than traditional networks,

more latency than traditional networks, less connection stability than other network tech￾nologies, and less predictable availability.

Mobile devices have a unique set of features that must be exposed in the Web, in

order to enable the creation of advanced telephony services that include location-based

services, intelligent network functionality, including integration into the voice network,

and voice/data integration.

The Wireless Application Protocol (WAP) architecture provides a scalable and extensible

environment for application development for mobile communication devices. The WAP pro￾tocol stack has a layered design, and each layer is accessible by the layers above, and by other

services and applications. The WAP layered architecture enables other services and applica￾tions to use the features of the WAP stack through a set of well-defined interfaces. External

applications can access the session, transaction, security, and transport layers directly.

5.1 WIRELESS APPLICATIONS AND DEVICES

Providing Internet and World Wide Web (WWW) services on a wireless data network

presents many challenges because most of the technology developed for the Internet has

been designed for desktop and larger computers that support medium to high bandwidth

connectivity over generally reliable data networks.

Mobile and wireless devices are usually handheld devices, and accessing the WWW

presents a more constrained computing environment compared to desktop computers

because of fundamental limitations of power and form factor. Mass-market handheld

wireless devices tend to have

• less powerful CPUs (Central Processor Units)

• less memory [both ROM (Read Only Memory) and RAM (Random Access Memory)]

Mobile Telecommunications Protocols For Data Networks. Anna Hac´

Copyright ¶ 2003 John Wiley & Sons, Ltd.

ISBN: 0-470-85056-6