Next Generation Wireless Applications: Creating Mobile Applications in a Web 2.0 and Mobile 2.0 World, 2nd Edition

6.1 THE GREATER CHALLENGES

Figure 6.1 reminds us of the basic structure of our mobile network within which the CS architecture is utilised to deliver mobile services. We can see that the device communicates over the RF and IP network layers to the server in the content network. Figure 6.2 is an alternative view of this model taken by slicing through the networks. We can use this alternative view to highlight several observations about the CS approach.

In most mobile services, we have a device at the top of the chain of events, as shown in Figure 6.2; we shall look at devices in depth later in Chapter 10. The next component in our chain is a set of protocols – a common language between the device and the server, represented symbolically by the arrow in the top half of the figure. The arrow represents two mechanisms. Firstly, the method of communication between the two ends, which for the current discussion will focus on HTTP and its wireless variant WSP from the WAP family of protocols. Secondly, we need a way of formatting the information passed by the protocol. As Chapter 5 discussed in some depth, the format of the data stored on the server or in a companion database server is not suitable for direct display on a device; it will be neither understandable by the device nor in a presentable format. As the figure shows, attempting to view the information in its native state will result in incomprehensible gibberish being displayed (the file snapshot on the far right). The alternative ...