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

7.6 WIRELESS PROTOCOLS – WTP AND WSP

7.6.1 Introduction

Having discussed the wireless profiles for TCP and HTTP, we have covered the main direction for WAP support in the future. However, the WAP 1 protocols are already in wide circulation in millions of devices and will continue to be used for some time to come as they are extremely efficient, especially on slower WAN links, like GPRS. Many newer devices will support both WAP 1 and WAP 2 stacks. These are not backwards compatible, so they have to be implemented as separate stacks on the device – WAP 2 will not handle a connection with a WAP 1 proxy (and vice versa). This does not mean that we need two browsers! The trend is for a single browser implementation that can handle all the various markup languages that have evolved within (and alongside) WAP. The browser will use either a WAP 1 or a WAP 2 stack to access the corresponding stack on the other end of the link, but it cannot use a WAP 1 stack to access a WAP 2 source (and vice versa).

WTP and WSP are not compatible in any way with TCP and HTTP – they are separate protocols, although similar in many respects. The design ethos for both these protocols is to facilitate the fetch–response paradigm in the most optimal manner. This is not like TCP, which is a generic protocol that has been designed to support many varied higher layer applications, not just web browsing (HTTP). TCP can support protocols like FTP for file transfer, telnet for remote terminal access, Simple Mail ...