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WIRELESS APPLICATION PROTOCOL

SEMINAR REPORT

Submitted in partial fulfillment of the requirement

of the award of

BACHELOR OF TECHNOLOGY

in

ELECTRONICS ENGINEERING

of

COCHIN UNIVERSITY OF SCIENCE AND TECHNOLOGY

By

SANJAY KRISHNAN

DEPARTMENT OF ELECTRONICS ENGINEERING

COLLEGE OF ENGINEERING

CHENGANNUR – 689 121

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THE WAP FORUM

The Wireless Application Protocol Forum is an industry group dedicated to the

goal of enabling sophisticated telephony and information services on handheld wireless

devices. These devices include mobile telephones, pagers, personal digital assistants

(PDAs) and other wireless terminals. Recognizing the value and utility of the World

Wide Web architecture, the WAP forum has chosen to align its technology closely with

the Internet and the Web. The WAP specification extends and leverages existing

technologies, such as IP, HTTP, XML, SSL, URLs, scripting and other content formats.

Ericsson, Motorola, Nokia and Unwired Planet founded the WAP Forum in June, 1997.

Since then, it has experienced impressive membership growth with members joining from

the ranks of the world’s premiere wireless service providers, handset manufacturers,

infrastructure providers, and software developers. WAP Forum membership is open to all

industry participants.

GOALS OF WAP FORUM

The WAP Forum has the following goals:

• To bring Internet content and advanced data services to Wireless phones and other

wireless terminals.

• To create a global wireless protocol specification that works across all wireless

network technologies.

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• To enable the creation of content and applications that scale across a wide range of

wireless bearer networks and device types.

• To embrace and extend existing standards and technology wherever possible and

appropriate.

• In order to accomplish these goals, the WAP Forum has developed the WAP

specification according to design principles as outlined below.

The WAP Forum seeks to use existing industry standards as the basis for

its own architecture and design. For example, a WAP Gateway is required to

communicate with other Internet nodes using standard HTTP 1.1 protocol. Furthermore,

the specification calls for wireless handsets to use the standard URL addressing scheme

to request services.

It is also very important for the WAP Forum’s specification in such a

way that they complement existing standards. For example, the WAPV1.0 specification is

designed to sit on top of existing bearer channel standards so that any bearer standard can

be used with the WAP protocols to implement complete product solutions. When the

WAP Forum identifies a new area of technology where a standard does not exist, or

exists but needs modification for wireless, it works to submit its specifications to other

industry standard groups.

BEARER INDEPENDNCE

To best address the needs of the widest possible population of end users,

the Wireless Application Protocol is designed to work optimally with all air interfaces. This

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principle allows the largest number of service providers, software developers, and handset

manufacturers to benefit from one unified specification. Service providers can implement a

common solution across their own disparate networks so that every subscriber has the best

possible user experience on each network. Applications can be developed using one

standard that will work across a variety of networks. Handset manufacturers can use the

same software in all of “their” products lines, reducing development time and simplifying

support issues.

By making minimal demands on the air interface itself, the WAP

specification can operate on the widest number of air interfaces. It defines a protocol

stack that can operate on the widest number of air interfaces. It defines a protocol stack

that can operate on high latency, low bandwidth networks such as Short Message Service

(SMS), or the upcoming GSM unstructured Supplementary Service Data (USSD)

channel. Being air interface independent also makes the specification easy to extend to

new networks and transports as they develop. As air interfaces become more

sophisticated, the services they provide can be designed to comply with the WAP

specification, further encouraging the use of one standard across all networks.

DEVICE INDEPENDENCE

In addition to being air interface independent , the WAP

specification is also independent of any particular device. Instead, it specifies the bare

minimum functionality a device must have, and has been designed to accommodate any

functionality above that minimum. Device independence offers similar benefits to bearer

independence: applications developed for one standard can operate on a wide variety of

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devices that implement the specification; network operators gain a consistent user

interface for their services across multiple vendors’ handsets ; application developers do

not have to write separate versions of their code for different

devices, and service providers can choose any standard compliant device that meets their

own unique market requirements. Device manufacturers are assured that they will have

many applications written for their device by implementing the specification, yet are able

to add their own brand features above and beyond the minimum standards to make their

device unique in the marketplace.

INTROPERABILITY

Service providers must feel secure that their investments will yield

benefits in the future. They will not be able to do so until equipment and software offered

by different suppliers can be made to work together. The WAP specification has been

designed to encourage easy, open interoperability between its key components. Any

solution component built to be compliant with the WAP specification can interoperate

with any other WAP compliant component. Service providers can choose equipment and

software from multiple WAP-compliant vendors, selecting each piece of the solution that

is appropriate for the service providers’ particular needs. Bearer and device independence

both help foster interoperability. But interoperability goes beyond these two principles to

require that each WAP- compatible component will communicate with all other

components in the solution network by using the standard methods and protocols defined

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in the specification. Interoperability provides clear benefits for handset manufacturrs and

infrastructure providers. Handset manufacturers are assured that if their device complies

with the WAP specification it will be able to interface with any WAP-compliant server,

regardless of the manufacturer. Likewise, the makers of a WAP-compliant server are

assured that any WAP-compliant handset will interface correctly with their servers.

ENCOURAGE AND FOSTER MARKET MANAGEMENT

The WAP specification is designed to bring Internet access to the

wireless mass market. By building open specifications, and encouraging communication

and technical exchanges among the industry players, the WAP Forum has already begun

to open the wireless data market in new ways. Just over a year ago, the idea of a single

wireless data standard was unheard of, yet today the WAP V1.0 specification is available

to the public, and dozens of companies are promoting this vision of the future. The

revolution is under way to bring information access to any handset, at a reasonable price

and in an easy to use form factor.

HOW WAP WORKS

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In the figure above, starting from the left, you'll find the

mobile WAP device attached to the mobile network (GSM, CDDA, etc) which dials the

modem attached to a dial-in server (RAS or Remote Access Service). This server gives

the WAP device access to the protocols it needs. These are the same lower level protocols

as a normal Internet Service Provider will give you. This is known as PPP or Point-to-

Point Protocol. These protocols are used to access the next step in the chain that is the

WAP gateway, in this figure hosted by the mobile operator. The WAP gateway is the link

between the wireless and the "web world, basically giving the WAP device access to the

common internet.

Another way of explaining it, and in a bit more detail would be to

say that when you type in the URL for a site on your WAP device, for instance

http://wap.colorline.no/ the WAP device first checks if it already has an open connection,

if not it dials up the PPP provider as described above. After the PPP provider has given

the WAP device the required protocols and assigned it an IP address, the request for the

URL is sent to the gateway. The WAP gateway, now under "control" of the WAP device

requests the URL with a normal HTTP request, such as GET http://wap.colorline.no/.

On the internet, there is a normal "web" server which in this

case holds both WAP and "web" contents, which now receives the request to send out the

contents located at the http://wap.colorline.no/ URL. Also note the normal "web browser

at the lower part of the figure. The web server depending on which type of browser it is

talking to

(WAP or "web"), sends out WAP, represented by the blue line, or "web" content

represented by the green line. Following the requested content back to the WAP device,

the contents, if they are in so called textual WML code (the human readable type), the

WAP gateway compiles the textual WML into so called tokenized WML, or WMLC,

where basically the code is "compressed" down into binary data (the machine readable

type). This tokenized WML is then passed back to the WAP device. If the contents from

the webserver are already in tokenized WML format, the WAP gateway skips this

operation.

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The reason for the conversion from texual WML to tokenized WML

is to reduce bandwidth usage. A WAP device's WML browser can only read tokenized

WML. Finally, back at the WAP device that requested the URL, the WML browser,

when receiving the tokenized WML code renders the contents on the WAP device's

display to present data sent back and forth between the web server and the WAP device,

they a card for the user. This is how the majority of WAP devices is connected to the

internet.

If the content provider wants pretty much total control over the

stream of would install something called a WAPserver. This device is merely a web

server and a WAP gateway in one, and it is usually located inside a firewall on the

content provider's networks. The WAP device gets internet access the same way as

before, but from there it now connects to the firewall which accepts or rejects the

connection depending on the firewall configuration. The firewall then passes the

connection on to the WAP gateway inside the WAP server. In this configuration, the

chain between the content server and the WAP device is point-to-point secured with the

WTLS encryption protocol.

The Wireless Markup Language (WML)

Many references use terminology such as "WML is derived from

HTML" or "WML is loosely based on XML". WML is, in fact, an XML document type

defined by a standard XML Document Type Definition, or DTD. The WML 1.1 DTD is

defined at:

http://www.wapforum.org/DTD/wml_1.1.xml




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Much greater detail on XML and WML are given in the WML tutorial located under the

WAP training topic, however the following code gives you an example of a simple WML

file.

<?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="First_Card" title="First Card">

<p>

Hello World!

</p>

</card>

</wml>

The first two lines are required. They give the XML version number and the public

document identifier, respectively. From there, all WML decks (one WML file equals one

deck) begin and end with the

<wml></wml>

tags. Individuals cards are arranged with the

<card></card>

tags. Also, note that WML, like XML, is case-sensitive!

Included in the WML specification are elements that fall into the following categories:

Decks/Cards, Events, Tasks, Variables, User Input, Anchors/Images/Timers, and Text

Formatting.

WMLScript

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The purpose of WMLScript is to provide client-side procedural logic. It is based on

ECMAScript (which is based on Netscape’s JavaScript language), however it has been

modified in places to support low bandwidth communications and thin clients. The

inclusion of a scripting language into the base standard was an absolute must. While

many Web developers regularly choose not to use client-side JavaScript due to browser

incompatibilities (or clients running older browsers), additional server-side scripts must

still replace this logic. This involves extra roundtrips between clients and servers, which

is something all wireless developers want to avoid. WMLScript allows code to be built

into files transferred to mobile client so that many of these round-trips can be eliminated.

According to the WMLScript specification, some capabilities supported by WMLScript

that are not supported by WML are:

• Check the validity of user input

• Access to facilities of the device. For example, on a phone, allow the programmer

to make phone calls, send messages, add phone numbers to the address book,

access the SIM card etc.

• Generate messages and dialogs locally thus reducing the need for expensive

round-trip to show alerts, error messages, confirmations etc.

• Allow extensions to the device software and configuring a device after it has been

deployed.

WMLScript is a case-sensitive language that supports standard variable declarations,

functions, and other common constructs such as if-then statements, and for/while loops.

Among the standard’s more interesting features are the ability to use external compilation

units (via the use url pragma), access control (via the access pragma), and a set of

standard libraries defined by the specification (including the Lang, Float, String, URL,

WMLBrowser, and Dialogs libraries). The WMLScript standard also defines a bytecode

interpreter since WMLScript code is actually compiled into binary form (by the WAP

gateway) before being sent to the client.

Why use WML when you can use HTML?

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First of all, the WAP specifications require the use of WML. You

might have heard of WAP devices that support HTML, but this really isn't the case. There

are several other wireless devices similar to WAP devices, but these use either straight

HTML (such as devices with the Microsoft Mobile Explorer, which supports both HTML

and WML. The MME devices are really two completely separate devices in one. Then

there are the variants on HTML such as the iMode browsers, which use Compact HTML.

In short, if we're talking about WAP devices, the markup language is WML. There are

many reasons why WML is used in the WAP environment instead of HTML. Currently

the most important reason is that WML requires very little bandwidth resources

compared to HTML. Obviously, with the introduction of technologies that provide higher

bandwidth for wireless devices, this reason becomes less important. However, it will take

many years before these higher bandwidth technologies are available globally. Another

important reason is that HTML requires relatively great processing strength to render.

Processing strength means power, and on a wireless device that means energy from

batteries. Less processor power means longer lasting batteries. Further, HTML really

requires larger displays than the display on a device such as a mobile phone. Sure, it's

possible to have large displays on mobile phones or other mobile device, but the larger

the device is, the less mobile it will be.

WAP PROTOCOL STACK

Any network is organized as a series of layers or levels where each level performs a

specific function. The set of rules that governs the communication between the peer

entities within a layer are called protocols. The layers and protocols together forms the

Protocol Stack. The request from the mobile device is sent as a URL through the

operator’s network to the WAP gateway, which is the interface between the operator’s

network and the Internet.

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WDP

The WAP datagram protocol (WDP) is the bottommost layer responsible for moving data

from sender to receiver and back again. WDP is patterned after UDP (User Datagram

Protocol) of the Internet, which is a best effort delivery protocol. Thus WDP is the

transport layer that sends and receives messages via any available bearer network,

including SMS, USSD, CSD, CDPD, IS-136 packet data and GPRS.

WTLS

Wireless transport layer security (WTLS), an optional security layer, has encryption

facilities that provide the secure transport service required by many applications, such as

e-commerce. WTLS incorporates security features that are based upon the established

Transport Layer Security (TLS) protocol standard. Includes data integrity checks, privacy

on the WAP Gateway to client leg and authentication. Wireless Datagram Protocol

Allows WAP to be bearer independent by adapting the transport layer of the underlying

bearer. WDP presents a consistent data format to the higher layers of the WAP protocol

stack thereby conferring the advantage of bearer independence to application

WTP

The WAP transaction protocol (WTP) layer provides transaction support adding

reliability to the Datagram service provided by WDP. It is loosely based on TCP/IP of

Internet. There are three different WTP transaction classes defined. The simplest

transaction class, class0 is a non-confirmed simple push of information in one direction.

This is used for basic information exchange. Transaction class1 is used for WAP1.1 Push

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transactions and is a simple send- acknowledgement exchange. Transaction class2 is a

three-way handshake used for most WSP/WTP information exchange. This handshake is

a send-acknowledgement-responsetrio sent from the iniator to the responder and back

again. WTP has the optional ability to segment and reassemble data.

WSP

The WAP session protocol (WSP) layer provides a lightweight session layer to allow

efficient exchange of data between applications. WSP is patterned after the HTTP

(Hypertext Transfer Protocol) of the Internet. WSP has two modes-when WSP is used in

conjunction with WTP, a session is initiated by the WAP client and is maintained until it

is explicitly disconnected. Such a mode is called WSP connection mode. Another mode is

WSP/B is in which no session is created, it is called temporary or connectionless WSP.

WAE

This layer defines the user interface on the phone. WAE is aimed at enabling operators,

content developers to develop advanced services and applications including a

microbrowser, scripting facilities, e-mail, www to mobile handset imaging and mobile to

telefax access.

HTTP Interface

The HTTP interface serves to retrieve WAP content from the Internet requested by the

mobile device. WAP content (WML and WML Script) is converted into a compact binary

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form for transmission over the air. The WAP microbrowser software within the mobile

device interprets the byte code and displays the interactive content.

STANDARDS

The collaborative efforts of the WAP forum have devised and continue to develop a set

of protocols that provide a common environment for the development of advanced

telephony services and Internet access for the wireless market. If the WAP protocols

were to be as successful as the transmission control protocol (TCP)/Internet protocol (IP),

the boom in mobile communications would be phenomenal. Indeed, the WAP browser

should do for mobile Internet what Netscape did for the Internet.

The many requirements for radio transmission technologies, proposed by the

International Telecommunication Union(ITU) and its International Mobile

Telecommunications for the year 2000(IMT-2000), include the following:

• Voice quality comparable to that of the public switched telephone network(PSTN);

• A data rate of 14.4 kbp/s for users in motor vehicles moving fast over large areas;

• A data rate of 384 kbp/s for pedestrians, standing still or moving slowly over small

areas;

• Phased-in-support for 2.048 Mb/s operation for office use;

• Support of both packed switched and circuit-switched data services;

•An adaptive radio interface suited to the highly asymmetric nature of most Internet

communications-a much greater bandwidth for the downlink than the up-link.

• More efficient use of the available spectrum;

• Support for a wide variety of mobile equipment; and

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• Flexible introduction of new services and technologies.

The WAP Gateway

The Wireless Internet Gateway (WIG) gives WAP and SIM

Application ToolKit (SAT) terminals access to WML-based applications. It brings WAP

to legacy terminals via SMS and supports end-to-end security, push and location-based

services. A SIM-based WML browser not only lets a GSM operator deliver web-style

content to the current large installed base of mobile phone subscribers, but it offers

increased security inherent in the SIM´s Smart Card technology. Since each subscriber

holds a unique encrypted digital signature in each phone´s SIM card, the WIG makes it

possible for operators to immediately add applications like e-commerce and online

banking, which capture the interest of security-conscious subscribers clamoring for more

financial transaction services.

The SIM-based WML browser for the WIG is available on most SIM platforms,

including Giesecke & Devrient, SetecGemplusSchlumberger and De La Rue (Oberthur).

SIM browser plug-in modules are also available to generate signatures and retrieve

location-based information. It is now possible for WML application programmers to

begin immediate deployment of location sensitive applications, and to support security

schemes based on the Public Key Infrastructure (PKI).

The WAP gateway is actually a software that performs several functions between the

WAP device and the Web server such as:

• Converting WML pages from server from textual format to binary/compressed format

readable by WAP device.

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• Translating requests from WAP device to HTTP requests for the Web world.

• Converts between SSL encryption used in Web and WTLS used in WAP>

• Converts between "transport" protocol that is TCP of the Web and WDP of WAP.

WAP Browser The Nokia WAP Browser is a platform independent version of the

same software currently running on Nokia's mobile phones and communicator class

products. It is a source code product and includes 100% WAP-compliant

implementations of both the WAP Application Environment (WAE) and the WAP

Protocol Stack (WPS). The Nokia WAP Browser was designed in accordance with the

embedded environments common in mobile telephones as well as the requirements

inherent in OEM software. It is ideally suited for the memory and processor constraints

commonly found in mobile telephones, and can also be augmented with additional

functionality when necessary.

Benefits:

Cost Effective

Licensing the Nokia WAP Browser is significantly more cost-effective than developing

in-house WAP implementations. As a WAP standard, it can become the foundation of

in-house development efforts.

Maintain Control

Nokia provides the source code and support - the customer pilots all further development.

Free from external development schedules.

Reduce Time-to-Market

Market-ready and market-tested

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Highly portable, reducing implementation time

WAP Security

SSL or Secure Sockets Layer which is widely used in the "web"

world to encrypt the data stream between the browser and the webserver is actually also

used in the WAP environment. However, SSL is only used between the webserver and

the WAP gateway. Between the WAP gateway and the WAP device, a similar system

called WTLS or Wireless Transport Layer Security. WTLS is specialized for the wireless

environment.

Security is a touchy subject. Althought no systems are totally secure,SSL and WTLS on their own in my humble opinion provide adequate security for most

applications. However, there is a potential security problem where the two protocols

meet, and that's inside the WAP gateway. SSL is not directly compatible with WTLS, so

the WAP gateway must decrypt the SSL protected data stream coming from the

webserver and then re-encrypt it using WTLS before passing the data on to the WAP

device. Inside the memory of the WAP gateway, the data is unprotected. This is the

current model:

| |

[WAP device]------------[WAP gateway]-----------[Content server]

<---WTLS--->{unprotected}<---SSL--->

| |

(Firewall) | | (Firewall)

Imagine if your bank or other institution dealing with sensitive data

make public a WAP service. When the data leaves the security of your system and your

network they are resonably well protected. Then, when they enter the WAP gateway

which is commonly owned and operated by a third party such as a mobile operator, the

data is decrypted. Trusting sensitive data to an unknown third party is hardly a good idea.

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The mobile operator in question could be any mobile operator in the world. Your

customer might be on vacation in some country where security is considered a trivial

matter. If the mobile operator's networks are vulnerable to attacks, so are your data. All

the major WAP players are developing solutions to this problem, but for now these

solutions create other problems.

Developers of so called "WAP servers", or webservers with WAP

gateway capabilities provide end-to-end security in a way because the data stream leaves

the content server (the "WAP server") already encrypted with WTLS. The model then

looks like this:

| |

[WAP device]------------------------------------["WAP server" (acting as WAP gateway)]

<---------------WTLS--------------->

| |


However, the mobile operator's WAP gateway can now no longer

be part of the chain, and the user has to reconfigure his WAP device to point to the "WAP

server" which will become the WAP gateway for this session. But, this WAP gateway

only provides access to this one service, and when the user wants to access his other

favourite WAP sites, he has to reconfigure his phone again. Some WAP devices are fairly

easy to reconfigure for someone with who can be bothered to read a manual, but some

WAP devices are extremely difficult to reconfigure. Adding to this problem is the fact

that many mobile operators place their Point-to-Point service where the mobile device

dials in to get on the internet, and their WAP gateway on the same private IP range

network, usually behind a firewall. This firewall is usually set up only to allow the HTTP

protocol on port 80 which is default for this protocol. The WAP gateway uses this port to

receive data from content servers on the internet, and that's all it really needs. When the

WAP device attempts to access another WAP gateway on the Internet, the firewall will

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stop them either because the firewall says that the IP address of the WAP device is not

allowed to route data on to the internet, or that it cannot open the ports it requires. This

effectively stops the user from using other gateways that the one provided by the mobile

operator.

There are lots of people suggesting solutions to this problem, and the

rumours say that upcoming versions of WAP will have a solution. In other words, a

model like this where the WAP gateway has two modes. A "normal mode" where it

works like WAP gateways work today, and a "passthrough" mode where the gateway

detects the WTLS stream and simply lets it pass through.

"Passthrough mode"

| |

[WAP device]------------[WAP gateway]-----------["WAP server"]

<---------------WTLS--------------->

| |


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WAP SOLUTION BENEFITS

The WAP V1.0 specification was written to address the challengesof traditional wireless data access within the context of the WAP Forum's design

objectives. This section outlines how the WAPV1.0 specification meets the goals.

DELIVERS AN APPROPRIATE USER EXPERIENCE MODEL

The WAP specification defines a powerful and functional user

interface model that is appropriate for handheld devices.Users navigate through cards

with up and down scroll keys instead of a mouse. Soft keys allow the user to perform

specific operations appropriate to the application context, or select menu options. A

traditional 12-key phone keypad is used to enter alphanumeric characters , including a

full set of standard symbols. Navigation functions such as Back, Home, and Bookmark

are also provided, in keeping with the standard browser model. By using the existing

Internet model as a starting point, this user interface provides familiar functionality for

those accustomed with the Web. It also provides a user interface that is easy to learn and

highly discoverable for the first time user. The microbrowser allows devices with larger

screens and more features to automatically display more content, just as a traditional

browser does on a PC when the browser window is expanded on screen.

LEVERAGES PROXY TECHNOLOGY

The WAP specification utilizes standard Web proxy technology to

connect the wireless domain with the Web. By using the computing resources in the

WAP gateway, the WAP architecture permits the handset to be simple and inexpensive.

For example, a WAP gateway will typically take over all DNS services to resolve domain

names used in URL's , thus offloading this computing task from the handset. The WAP

gateway can also be used to provision services to subscribers and provides the network

operator with a control point to manage fraud and service utilization. A WAP gateway

typically includes following functionality:

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• Protocol Gateway- the protocol gateway translates requests from the WAP

protocol stack to the WWW protocol stack(HTTP and TCP/IP).

• Content Encoders and Decoders-the content encoders translate web content into

compact encoded formats to reduce the size and number of packets travelling over

the wireless data network. This infrastructure ensures that mobile terminal users

can browse a wide variety of WAP content and applications regardless of the

wireless network they use. Because of the WAP proxy design,content and

applications are hosted on standard WWW servers and can be developed using

proven web technologies such as CGI scripting.

The WAP gateway decreases the response time to the handheld

device by aggregating data from different servers on the web, and caching frequently

used information. The WAP gateway can also interface with subscriber databases and use

information from the wireless network, such as location information, to dynamically

customise WML pages for a certain group of users.

ADDRESSES CONSTRAINTS OF WIRELESS NETWORK

The protocol stack defined in WAP version 1.0 optimizes standard

Web protocols, such as HTTP, for use under the low bandwidth, high latency conditions

often found in wireless networks. A number of enhancements to the session, transaction,

security and transport layers provide HTTP functionalilty better suited to the wireless

network environment. Here are just a few examples of these improvements:

• The plain text headers of HTTP are translated into binary code that significantly

reduces the amount of data that must be transmitted over the air interface.

• A lightweight session re-establishment protocol has been defined that allows

sessions to be suspended and resumed without the overhead of initial

establishment. This allows a session to be suspended while idle to free up network

resources or save battery power.

• WAP V1.0 provides a Wireless Transaction Protocol(WTP)that provides reliable

datagram service, much as traditional TCP does, but without behaviors that make

TCP unsuitable in a wireless network. For example, TCP transmits a large amount

of information for each request-response transaction, including information

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needed to handle out of order packet delivery. Since there is only one possible

route between the WAP proxy and the handset, there is no need to handle this

situation. WTP eliminates this unnecessary information, and reduces the amount

of information needed for each request-response transaction.

• WAP's WTP solution also means that a TCP stack is not required in the phone,

which allows for significant savings in processing and memory costs in the

handset.

• The improvemnets made in the WAP protocol stack lead to significant savings in

wireless bandwidth. Figure 3 compares the number of packets needed to process a

stack quote query from a desktop browser using HTTP 1.0 with the same query

from a WAP browser. The WAP protocol uses less than half the number of

packets that the standard HTTP/TCP/IP stack uses to deliver the same content.

This improvement is essential to best utilize the limited wireless bandwidth

available.

PROVIDES A SECURE WIRELESS CONNECTION

Many applications on the Web today require a secure connection

between the client and the application server. The WAP V 1.0 specification ensures that a

secure protocol is available when these transactions with the wireless handset. The

Wireless Transport Layer Security(WTLS) protocol is based upon the industry standard

Transport Layer Security(TLS) protocol, formerly known as the Secure Sockets

Layer(SSL). WTLS is intended for use with the WAP environment and has been

optimized for use over narrow band communication channels. WTLS ensures data

integrity, privacy, authentication and denial of service protection. For Web applications

that employ standard internet security techniques with TLS, the WAP gateway

automatically and transparently manages wireless security with minimal overhead.

OPTIMIZE FOR HANDHELD WIRELESS DEVICES

The WAP V1.0 specifiaction defines a microbrowser that is the

ultimate thin client, able to fit in a limited amount of memory in the handheld device. The

use of proxy technology and compression in the network interface reduces the processing

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load at the handheld device so that expensive CPU can be used in the handset. This

further helps reduce power consumption and extends battery life meeting the needs of

both handset manufacturers and wireless subscribers.

IMPLEMENTS NEW WIRELESS FUNCTIONALITY

The WAP V1.0 specification also defines new functionality that has

not been defined by any other standard, such as a voice/data integration API and the

groundwork for wireless push functionality. The Wireless Telephony Application (WTA)

allows application developers to initiate phone calls from the browser, and respond to

network events as they occur. The WTA API accomplishes this by providing and

interface to the local and network telephony infrastructure. This functionality can be used

to keep an updated list of the phone numbers dialed into an active conference call.

Standard HTTP has no support for "push" functionality. The WAP

V1.0 specification defines a push mechanism that will allow any web server to send

information to the client. WAP Forum is currently defining the higher level protocols

needed to provide a complete wireless push solution. This allows applications to alert the

subscriber when time-sensitive information changes like traffic alerts and stock quote

triggers.

ENABLES APPLICATION DEVELOPMENT USING EXISTING TOOLS

Web developers find it easy to develop WAP applications since the

WAP Programming model closely follows the existing WWW development model.

WML is a tag-based document language specified as an XML document type. WML

developers can use standard web tools and mechanisms such as Cold Fusion, CGI, PERL

and ASP to generate dynamic WML applications.

Although it is possible to translate HTML into WML using an

automated system, in practice the best applications use WML to tailor the interface to the

specific needs of the wireless user. This allows for the best possible use of the handset

features, such as soft keys and provides the best user experience. Therefore developing a

corresponding WML front-end leverages previous engineering effort while providing

significant user interface benefits.

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BENEFITS FROM WAP BASED SOLUTIONS

SERVICE PROVIDERS

Service providers can add significant value to their existing voice

offerings by adding a WAP based solution to their wireless networks. By choosing a

WAP based solution to deploy wireless data, network operators will gain:

• A whole new dimension of relationship and communication with their

subscreibers. This creates new opportunites for improved customer service and

increased usage of network services.

• Control of data connection to their subscribers. By using a WAP based solution,

service providers can use the WAP gateway to track and bill for the service, and

provision general feature control.

• An easy method to deploy Teleservices applications, such as Call Feature Control,

prepaid wireless recharge and automated customer service. Since the applications

are stored on a standard web server inside the service provider's infrastructure,

when new services are added, or features are changed, these changes are instantly

available to every subscriber in the network.

• Immediate access to all WAP enabled wireless content. Since WAP is a

specification that many developers are using, service providers will benefit from

an abundance of available content.

DEVELOPERS

Application developers can reach the largest possible audience

when they write their applications in WML because they are writing to an industry

standard. Additional benefits for developers include:

• Access to an entirely new immense market of information hungry wireless

subscribers.

• Because WML is an XML based language, it is an easy markup language for

existing web developers to learn.

• WML's basis in XML also positions it well as a future target markup language for

automatic content transformation.

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• Since WML is part of an open standard, and was developed by an independent

organization, all developers can be assured that they are on equal footing with

other developers.

• By writing in WML, a developer's work becomes available to any network and

device that is WAP complaint.

• WML provides the application developer with the power to take full advantage of

the user interface. Applications can map soft keys for easy use of input and use

special features to maximise the effect of displaying text on a limited screen.

• WML allows application developers to integrate their applications with device

and network telephony functions.

• WML allows the user icons and bitmapped graphics, for devices that support

them.

• An application written in WML will look good on any device that is WAP

complaint. If one device is able to display more lines of text than another, the

microbrowser will do so automatically, making the best use of device's and

application's capabilities.

• An application can be customized to take advantage of a particular device's

capabilities, by using standard HTTP header mechanisms to learn about the

device's capabilities, so that the application can dynamically generate the

appropriate content.

• Developers who are converting existing HTML pages into WML will find that

that their investment in databases, proprietary content, application logic and API's

is preserved with WML.

SUBSCRIBERSUltimately, subscibers are the most important beneficiaries of the

work of the WAP Forum. As a result, the WAP specifiaction delivers significant value to

the subscriber.

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The WAP specification pulls together existing technologies and defines new standards to

provide subscribers with:

• Fast, efficient access to key information from a wireless handset.

• Peace of mond that all transactions are completely secure.

• An easy to use interface metaphor that meets the needs of the user within the

restrictions of a constrained network and device.

WAP—USES

! E-mail : : Using WAP phones, one can access and exchange e-mails.

! Personalised information access : The user could maintain a

phone book or an address book on a WAP-enabled phone.

! Events-calendar management : The user could schedule his events

and maintain a calendar on the WAP phone.

! Personal banking : Banking and insurance are purported to be the other

sectors where WAP is predicted to make a significant difference. In banking, for

instance, a WAP gateway can provide user access to payment services. For example.

The Delhi-based, Nucleus Software that created a WAP software called, Bank-o-netto help banks WAP enable their services.

! Personal billing information: : This enables the user to perform

online shopping as well as make online payments.

!Customer care application : Information that is of interest to the

customer is provided by the operator.

! Financial information, stock quotes : Financial transactions are

expected to lead as a popular service available to WAP phone users. A service

category more suited to be successful on WAP enabled phone is live stock updates.

The phone can easily beep the subscriber when the favorite scrip jumps the cut off

mark and thereafter help him transact.

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!City direction guides : The user can obtain small road maps on his WAP

phone which will guide him.

! Infotainment : This includes interactive information as well as other

entertainment like games and chat.

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WAP PITFALLS

Presently though this technology is the blue eyed baby of the industry, its growth is

dependent on several factors that includes:

# WAP services—expensive: Most WAP based services used CSD (Circuit Switched

Data) as its underlying bearer. So the cost poses a deterrent as CSD requires its users

to remain connected to the network for full interaction.

# Difficult to configure WAP phones for new WAP services: When it is required to

introduce new services, about 20 or more different parameters must be entered and

with the limited user-interface, this becomes difficult.# WAP standard—incomplete with key elements like PUSH: There are different WAP

versions like WAP 1.0, WAP 1.1, WAP 1.2 and WAP 2.0. The current WAP standard

is WAP 1.1 which does not support the PUSH (Proactive sending of information to

mobile devices) function. PUSH was added to WAP 1.2, and is only available in

WAP 1.2 environments. In short PUSH provides another way of sending data from a

content or application server to a mobile user agent. The "traditional" way, PULLing

is for the user agent to request the information, and then receive it. PUSH means that

the server can send the data to the user agent without it having to ask for it. The

content or application server cannot send the data to the user agent directly, but will

have to use a so-called Push Proxy Gateway. This PPG sits between the internet

based Push Initiator (the content or application server) and the mobile user agent. On

the Internet side, the Push Access Protocol is used, and on the mobile Internet side,

the Push Over-the-Air Protocol is used.

# Small screen of WAP device: For example, the NOKIA 7110 has a screen size of 96

by 65 pixels, which can give only text specific data , it cannot have any graphics or

visual elements.

# Data rate in WAP-slow: The current wireless applications and its usefulness is limited

by the lower bandwidth that is about 9.6Kbps. With the advent of GPRS, the data rate

can be increased upto 117Kbps.

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