The basics of WAP technology

How WAP works

This article is the first installment in a two-part series on WAP (Wireless Application Protocol). In this article, I’ll discuss the basics of WAP technology. In part 2, the emphasis will be on using WAP in the enterprise, and I’ll focus on how to port SQL Server data to a WAP phone emulator using a sample application.  You can get to part 2 by clicking here
WAP basics
What is WAP anyway? Basically, WAP is a global standard developed by the WAP Forum for wireless devices to access the Internet and telephony services. WAP can also be used to access data from corporate intranets through public or private IP networks. Figure A shows the WAP services that are currently offered.

Figure A

WAP specifications
WAP is an open specification that defines a set of protocols in application, session, transaction, security, and transport layers. To leverage existing programming and development skills, it is based on existing standards and protocols such as XML, HTTP, UDP, HTML, and JavaScript.

The key elements of the WAP specification include:
  • A well-known applications development framework. The WAP transport model is analogous to the Internet model, except for the gateway that is inserted between the Web server and the client. This familiar model leverages the existing development skills of WWW programming.
  • WML (Wireless Markup Language) as the standard markup language.
  • A browser inside WAP devices that parses WML and WMLScript.
  • A framework to support advanced telephony services, like WWW to mobile messaging, call forwarding, mobile to telefax access, and address book access.

Figure B compares a protocol stack based on the Internet model to WAP. As you can see, numerous networks are included in WAP, with the ultimate goal of targeting multiple networks.

Figure B

How WAP works
A typical WAP network consists of the following components:
  • User with WAP-enabled device
  • Gateway
  • Application server

The application server can be located in either a public or private IP network. The gateway normally is located in telecom networks, but it can be set up by a company using its own computer systems. To get an idea of how these components work together, let’s look at a typical scenario using WAP technology:
  1. A user with a WAP device requests content from the application server.
  2. The request reaches the gateway first, which does the protocol translation from WAP to HTTP and routes the HTTP request to the destination server.
  3. The server returns WML output and adds HTTP headers to the gateway, depending upon whether dynamic or static pages are requested.
  4. The gateway converts WML and HTTP to binary form to conserve bandwidth and returns a WAP response to the user.
  5. The browser inside the WAP device interprets the WML and shows the contents.

WAP limitations
Compared to PCs, wireless devices are limited in terms of processing power, memory, battery life, and display size. Other issues of low bandwidth, latency, and connection stability motivated the forum to come up with a new set of WAP standards. They have reused many of the existing standards while creating new extensions to address the above-mentioned problems. The new WAP specifications leverage the existing investment in hardware, software, applications, and development skills.

The WAP marketplace
The drive toward WAP-enabled devices is gathering momentum. The WAP Forum, a consortium of 90 percent of the world's key handset manufacturers, has announced the upcoming release of WAP–compatible handsets. According to the forum, in less than two years, all new digital handheld devices will be WAP-enabled. Business technology advisor Gartner predicts that the mobile phone will become the most widely used Internet access device in the world, with the number of installed mobile phones topping 1 billion after 2003.

Online applications and services that do not transfer a large amount of information across a network will fuel most of WAP’s success. Services such as stock quotes, news, weather, and sports are already operational. As mobile commerce (m-commerce) becomes a faster, more secure channel, services such as banking, retail coupons, wireless ticketing, and sales notification will become commonplace. Look for this technology to change the way we interact with the Internet.

Now that you have a basic understanding of WAP, my next article will show you some real-world applications using this technology.
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