WAP- An Extension of the Internet Model

The WAP model closely resembles the Internet model of working. In Internet a WWW client requests a resource stored on a web server by identifying it using a unique URL, that is, a text string constituting an address to that resource. Standard communication protocols, like HTTP and Transmission Control Protocol/Internet Protocol (TCP/IP) manage these requests and transfer of data between the two ends. The content that is transferred can either be static like html pages or dynamic like Active Server Pages (ASP), Common Gateway Interface (CGI), and Servlets.

The following figure helps draw a parallel to the Internet protocols. You can see how WAP extends or reuses Internet protocols to achieve mobile Internet access.

The strength of WAP (some call it the problem with WAP) lies on the fact that it very closely resembles the Internet model. In order to accommodate wireless access to the information space offered by the WWW, WAP is based on well-known Internet technology that has been optimized to meet the constraints of a wireless environment. Corresponding to HTML, WAP specifies a markup language adapted to the constraints of low bandwidth available with the usual mobile data bearers and the limited display capabilities of mobile devices - the Wireless Markup Language (WML). WML offers a navigation model designed for devices with small displays and limited input facilities (no mouse and limited keyboard). WAP also provides a means for supporting more advanced tasks, comparable to those solved by using for example JavaScript in HTML. The solution in WAP is called WML Script. You will find more information about these later in the coming sections.

The following figure will give a clear understanding of the WAP model.

Source: Au systems white paper