1. Similarity with WWW model
i. WAP is a set of protocols that allow wireless devices like hand-held cell phones to access the internet. But it has programming model similar to that of WWW.
ii. WAP content and applications are specified in a set of well-known content formats based on WWW content formats
iii. Transport of content is based on standard communication protocols which are based on that of WWW. The micro browser is analogous to standard web browser.
iv. Wherever possible, existing standards are adopted, there are also some extensions to match characteristics of wireless environment.
v. This has provided benefits to application developers and ability to use existing tools (eg. XML tools)
Fig1. WAP Protocol Stack
2. Standard components of WAP programming model
i. Standard naming model: WWW standard URLs identify WAP content on origin servers and local resources in a device (eg. Call control functions)
ii. Content typing: all WAP content has a specific type consistent with WWW content types.
iii. Standard content formats: WAP content formats are based on WWW technology and include display markup, calendar information, electronic business card objects, images and scripting language.
iv. Standard protocols: the WAP communication protocols and content types are optimized for mass market, hand-held wireless devices. The protocols enable the communication of browser requests from mobile terminal to network web server.
3. Functionality of WAP proxy: WAP utilizes proxy technology to connect between wireless domain and WWW.
i. Protocol gateway: it translates requests from WAP protocol stack to WWW protocol stack.
ii. Content encoders and decoders: the encoders translate the content into compact encoded formats to reduce the size of data. Thus, mobile users can browse wide variety of WAP content. Also, application author is able to build applications that run on large number of mobile devices.
iii. WAP proxy allows content and applications to be hosted on WWW servers and to be build using WWW technologies like ‘Cell global identity (CGI)’ scripting.
Fig2. WAP Programming Model
4. WAP Architecture
i. It provides a scalable and extensible environment for application development of mobile
ii. This is achieved using layered design of protocol stack. The layers resemble the layers of OSI model.
iii. Each layer is accessible by layers above as well as by other services and applications through a set of well defined interface.
iv. External applications may access session, transaction, security and transport layers directly.
Fig3. WAP Architecture
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