Lesson 1: Introduction to WAP
At the time of writing, the backlash against the mobile Internet is going strong. This is in major part a response to the massive hype that accompanied the first WAP-enabled handsets in 1999-2000. Whilst these devices were marketed as windows onto the Internet, their limitations soon became obvious. Not only were they unable to show most Internet content, with little content of their own, they were also very slow to connect and navigate.
This backlash is itself a creature of hype, however; as out of touch as the original euphoria. In a world grown accustomed to the capabilities of the wired Internet, it is easy to forget that the mobile Internet is still at a very early stage of development. In the next five years we will see much faster, 'always-on' networks. We will also see a range of functions taking advantage of browser location-awareness, providing services tailored just for portables. So, the mobile Internet is going to have a strong future. And - as with the wired Internet - the most successful developers will be those who get in early, ahead of the crowd.
Background to WAP
WAP - the Wireless Application Protocol - is a suite of network protocols that specify ways of sending data across the airwaves. As with such protocol suites, they are organised hierarchically. At the bottom there are low-level protocols that are concerned with establishing connections, coding alphanumeric characters, etc. At the top there are the high-level protocols such as WML - the Wireless Markup Language - which is concerned with passing page information.
This set of tutorials is concerned with WML. Being web programmers, rather than network engineers, this is what we're interested in. But if you're interested in the other WAP protocols, you should be able to find them at http://www.wapforum.org/(on the wired Internet).
WAP as a whole has been designed to take into account various limitations in handsets and networks. Because the networks are slow, and the handsets unable to carry much memory or power, an effort has been made to make all of the elements as efficient as possible. It is not clear at present whether any of this efficiency has been gained at the cost of functionality - if so, then WAP will be under threat when the fast mobile networks are commonplace and handset technology has improved. But if other things remain equal, then WAP's efficiency will continue to contribute towards its success.
Developing WML
WAP protocols are not the same as web (HTTP) protocols. However, WML content can be stored on web servers. WML content is served up to mobile phones (and other portables) by passing through 'gateways' which stand at the borders of WAP and web networks. These gateways provide the appropriate translation between the two types of network. Even better, the gateways are provided by one's mobile phone network provider, so a WML developer doesn't have to worry about personally installing any gateway software.
Unfortunately, in order to host WML content one's web server does need to be set up to output five unusual MIME types. Supporting these MIME types ought to be an easy task, but it is interesting how few commercial ISPs have got round to doing it. If you are unable to host WML content on your usual ISP then try the free space at http://www.wapdrive.com/. The only other thing to do to develop WML content is to go through all of these tutorials, understand and learn them. Good luck!
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