Wap architecture and wml script

1. Mehta Ishani
130040701003
WAP architecture and WML Script
INTRODUCTION
WAP stands for Wireless Access Protocol.The WAP is the leading standard for information
services on wireless terminals like digital mobile phones.The WAP standard is based on Internet
standards (HTML, XML and TCP/IP).
PURPOSE
WAP stands for Wireless Access Protocol, a general term used to describe the multi-layered
protocol and related technologies that bring Internet content to mobile devices such as PDAs and
cell phones.
Such devices are referred to as thin clients because they have one or more constraints in the
form of display, input, memory, CPU, or other hardware or usability limitations. The platform
constraints and the slower (and more expensive) bandwidth of cellular and related networks
make standard Internet protocols difficult to utilize.
To enable easy, fast delivery of relevant information and services to mobile users WAP is
invented. It consists of a WML language specification, a WML Script specification, and a
Wireless Telephony Application Interface (WTAI) specification
BACKGROUND
As previously stated, WAP refers to a wide range of technologies and protocols, all related to
mobile Internet functionality. This functionality has roots dating back to the mid 1990s. At that
time, several vendors were working on the mobile Internet problem as mobile device sales
skyrocketed, and several competing technologies emerged:
WAP is published by the WAP Forum, founded in 1997 by Ericsson, Motorola, Nokia, and
Unwired Planet. Forum members now represent over 90% of the global handset market, as well
as leading infrastructure providers, software developers and other organizations.
HOW IT WORKS?
This document will focus on the delivery of WML content to mobile devices over a cellular or
related technology network. However, the delivery of many protocols and technologies takes the
same route namely, through a proxy server that bridges the gap between the wired Internet and
the wireless service provider's network.

2. Mehta Ishani
130040701003
Figure 1.1 WEB Model of WAP
This proxy server manages the communication between the wireless client and the Internet
server(s), acting as a gateway to the wired Internet. It caches content and in some cases even
translates raw HTML into WAP-compatible protocols such as WML.
Figure 1.2 the WAP Gateway provides wireless networks with Internet access and content
translation.

3. Mehta Ishani
130040701003
1. The user selects an option on their mobile device that has a URL with Wireless Markup
language (WML) content assigned to it.
2. The phone sends the URL request via the phone network to a WAP gateway, using the
binary encoded WAP protocol.
3. The gateway translates this WAP request into a conventional HTTP request for the
specified URL, and sends it on to the Internet.
4. The appropriate Web server picks up the HTTP request.
5. The server processes the request, just as it would any other request. If the URL refers to a
static WML file, the server delivers it. If a CGI script is requested, it is processed and the
content returned as usual.
6. The Web server adds the HTTP header to the WML content and returns it to the gateway.
7. The WAP gateway compiles the WML into binary form.
8. The gateway then sends the WML response back to the phone.
9. The phone receives the WML via the WAP protocol.
10. The micro-browser processes the WML and displays the content on the screen.
WAP PROTOCOL STACK
There are different layers in WAP Protocol Stack

4. Mehta Ishani
130040701003
WAE- (Wireless Application Environment)
It is for device specifications and the content development programming languages,
WML and WML Script.
WSP – (Wireless Session Protocol)
It is lightweight session layer to allow efficient exchange of data between applications.
WTP - (Wireless Transaction Protocol)
It provides transaction support, uses UDP suitable for low bandwidth wireless stations.
WTLS – (Wireless Transport Layer Security)
It has encryption facilities that provide the secure transport service required by many
applications, such as e-commerce. It includes data integrity checks, privacy, service denial, and
authentication services.
WDP – (Wireless Data link Protocol)
The WDP presents a consistent data format to the higher layers of the WAP protocol
stack, thereby offering the advantage of bearer independence to application developers.
WML
A markup language - the Wireless Markup Language (WML) has been adapted to
develop optimized WAP applications. In order to save valuable bandwidth in the wireless
network, WML can be encoded into a compact binary format. Encoding WML is one of the tasks
performed by the WAP Gateway/Proxy.
<?xml version="1.0"?>
<!DOCTYPE wml PUBLIC "-//WAPFORUM//DTD WML 1.2//EN"
"http://www.wapforum.org/DTD/wml12.dtd">
<wml>
<card>
...
</card> .
..more cards...
</wml>

5. Mehta Ishani
130040701003
WMLS
WMLScript (Wireless Markup Language Script) is the client-side scripting language of
WML (Wireless Markup Language). A scripting language is similar to a programming language,
but is of lighter weight. With WMLScript, the wireless device can do some of the processing and
computation. This reduces the number of requests and responses to/from the server.
Syntax
function name (parameters)
{
control statements;
return var;
}
WML Script to implement calculator functionality
Calc.wml
<?xml version="1.0"?>
<!DOCTYPE wml PUBLIC "-//WAPFORUM//DTD WML 1.1//EN"
"http://www.wapforum.org/DTD/wml_1.1.xml">
<wml>
<card id="card1" title="calc" newcontext="true">
<p>
Enter value of a: <input format="*N" name="a" title="A:"/>
<br/>
Enter value of b: <input format="*N" name="b" title="B:"/>
Operation: <select name="op" value="ADD" title="OP:">
<option value="ADD">Addition</option>
<option value="SUB">Substraction</option>
<option value="MUL">Multiplication</option>
<option value="DIV">Division</option>
</select>
<br/> $(a) $(op) $(b) = <u>$(conversion)</u>
<do type="accept" label="Calculate">
<go href="calc.wmls#convert('conversion','$(op)',$(a),$(b))"/>
</do>
</p>
</card>
</wml>

6. Mehta Ishani
130040701003
Calc.wmls
/*
*@param varName - the variable to store the results
*@param a - the value of a
*@param b - the value of b
*@param op - the operation
*@return a string containing the converted amount; or an
error if "op" is not supported.
*/
extern function convert(varName,op,a,b)
{
var returnString = "Not Available";
var result;
if (op == "ADD")
result = a + b;
else if (op == "SUB")
result = a - b;
else if (op == "MUL")
result = a * b;
else if (op == "DIV")
result = a / b;
if (b != 0.0)
{
returnString = String.toString(result);
returnString = String.format("%.2f", returnString);
}
/*
* Return the results to the browser
*/
WMLBrowser.setVar(varName,returnString);
WMLBrowser.refresh();
}

7. Mehta Ishani
130040701003
WAP - Core Services
 Banking
 Finance
 Shopping
 Ticketing
 Entertainment
 Weather
 E- Messaging
Advantage
The advantages that WAP can offer over these other methods are the following: open
standard, vendor independent network-standard independent transport mechanism optimised for
wireless data bearers application downloaded from the server, enabling fast service creation and
introduction, as opposed to embedded software