Wireless Application Wireless Application ProtocolProtocol

Prepared byPrepared bySukruti KaulgudSukruti Kaulgud

WAP and the World Wide Web (WWW) Wireless application protocol (WAP) is a set of

protocols WAP incorporates wireless markup language

(WML) WAP is very similar to the combination of

hyper text markup language (HTML) and hyper text transport protocol (HTTP)

It adds one very important feature: optimization for low-bandwidth, low-memory, and low-display capability environment.

WAP and the World Wide Web (WWW) WAP approach is content distribution similar to

web approach Both concentrate on distributing content to

remote devices using inexpensive, standardized client software.

Both rely on back-end servers to handle user authentication, database queries, and intensive processing.

Both use markup languages derived from standard generalized markup language (SGML) for delivering content to the client.

Introduction

WAP takes a client server approach

Incorporates a relatively simple microbrowser into the mobile phone

WAP puts the intelligence in the WAP Gateways

WAP specifies a proxy server that acts as a gateway between the wireless network and the wireline Internet, providing Protocol translation and optimizing data transfer for the wireless handset.

Goals of wireless application protocol: Independent of wireless network standards Interoperability: Terminals from different manufacturers must be

able to communicate with services in the mobile network Adaptation to bounds of wireless networks: Low bandwidth, high

latency, less connection stability Adaptation to bounds of wireless devices: Small display, limited

input facilities, limited memory and CPU, limited battery power Efficient: Provide quality of service (QoS) suitable to the behavior

and characteristics of the mobile world Reliable: Provide a consistent and predictable platform for

deploying services Secure: Enable services to be extended over potentially

unprotected mobile networks while preserving the integrity of data

Goals of wireless application protocol: Applications scale across transport options Applications scale across device types Extensible over time to new networks and transportWAP is envisaged as a comprehensive and scalable protocol

designed for use with: Any mobile device from those with a one-line display to a smart

phone Any existing or planned wireless service such as the SMS, circuit-

switched data and GPRS Any mobile network standard such as code division multiple

access (CDMA), global system of mobile communications (GSM), or universal mobile telephone system (UMTS).

WAP has been designed to work with all cellular standards and is supported by major worldwide wireless leaders

The WWW Model

Provides a flexible and powerful programming model.

Applications and content are presented in standard data formats, and are browsed by applications known as web browsers

The WWW Model Several mechanisms necessary to

build a general-purpose application environment includes

1. Standard naming model2. Content typing3. Standard content formats4. Standard protocols

The WWW Model The WWW protocols define three

classes of servers:

1. Origin server2. Proxy3. Gateway

The WAP Model WAP defines a set of standard

components that enable communication between mobile terminals and network servers, including:

1. Standard naming model2. Content typing3. Standard content formats4. Standard protocols

WAP GATEWAY1. Protocol gateway

WAP GATEWAY Content encoders and

decoders:1. Content encoders translate Web content into

compact encoded formats to reduce the size and number of packets.

2. The WAP Gateway decreases the response time to the handheld device by caching frequently used information.

3. The WAP Gateway can also interface with subscriber databases.

WAP SERVER A WAP server is simply a combined

web server and WAP gateway.

By combining the web server and the WAP gateway it is possible to enhance the overall security in these operations involved.

The WAP Model

The Network Is Different Less bandwidth

High latency

Less predictable availability

The Device Is Different

The Device Is Different Less powerful CPUs Less memory (ROM and RAM) Restricted power consumption Smaller displays Different input devices (e.g., a

phone keypad, voice input, etc.)

WAP Architecture They are: • Application Layer Wireless Application Environment

(WAE) • Session Layer Wireless Session Protocol (WSP)

WAP Architecture • Transaction Layer Wireless transaction protocol (WTP) • Security Layer Wireless Transport Layer Security

(WTLS) • Transport Layer Wireless Datagram Protocol (WDP)

WAP Architecture

WAP Architecture

WAP Architecture Wireless Application

Environment

1. Addressing model2. Wireless markup language3. WML Script

WAP Architecture Wireless Telephony Application

WAP Architecture Wireless Telephony Application

1. Wireless telephony application interface (WTAI)

2. Repository3. Event Handling4. WTA service indication

WAP Architecture Wireless Session Protocol1. Establish a reliable session from the client

to the server and release the session in an orderly manner.

2. Agree on a common level of protocol functionality using capability negotiation.

3. Exchange content between client and server using compact encoding.

4. Suspend and resume the session.5. Provide HTTP 1.1 functionality.6. Exchange client and server session

headers.

WAP Architecture Wireless Transaction Protocol

1. Class 02. Class 13. Class 2

WAP Architecture Wireless Transport Layer

Security

1. Data integrity2. Privacy3. Authentication4. Denial-of-service protection

WAP Architecture Wireless Datagram Protocol The services offered include application

addressing by port numbers, optional segmentation and reassembly, and optional error detection.

Supports several simultaneous communication instances from a higher layer over a single underlying WDP bearer service.

Adaptation layer Wireless control message protocol (WCMP)

Optimal WAP Bearers The bearers offer differing levels of

quality of service with respect to throughput, error rate, and delays.

1. Short message service (SMS)2. Circuit switched data (CSD)3. Unstructured supplementary

services data (USSD)4. General packet radio service (GPRS)

Traditional WAP Networking Environment

Traditional WAP Networking Environment The major players are the wireless

service provider (WSP) and the enterprise

Role of the WSP is to provide access to back-end resources for wireless users

WSP’s space contains a modem bank, remote access service (RAS) server, router, and potentially a WAP gateway.

Traditional WAP Networking Environment The modem bank receives incoming

phone calls from the user’s mobile device

RAS server translates the incoming calls from a wireless packet format to a wired packet format

The router routes these packets to correct destinations.

The WAP gateway is used to translate the WAP into traditional Internet protocol (TCP/IP)

WAP Advantages Implementation near to the

Internet model Most modern mobile telephone

devices support WAP Real-time send/receive data No hardware obsolescence

WAP AdvantagesAdvantages of using WAP CSS on mobile Internet sites: Because of WAP 2.0 (XHTML MP/WAP CSS), web

programming and WAP programming converge You can have greater control on the appearance

of WAP pages with WAP CSS than with WML A single cascading style sheet to the whole

mobile Internet site WAP CSS has the advantage that the content

and presentation can be separated.

WAP Disadvantages

Low speeds, security, and very small user interface

Not very familiar to the users Business model is expensive

WAP DisadvantagesDisadvantages of using WAP CSS style

sheets on mobile Internet sites are Different WAP browsers have varied

levels of support for WAP CSS If you make use of a single WAP CSS

file the file size of the WAP CSS file can be quite large

Applications of WAP Accessing the Internet from mobile devices Games can be played from mobile devices To locate WAP customers geographically WAP also provides short messaging, e-

mail, weather, and traffic alerts based on the geographic location of the customer

Biggest applications of WAP under consideration is banking from mobile devices

imode imode is a proprietary mobile ISP

and portal service from NTT DoCoMo, Japan

imode uses compact HTML (cHTML) as a page description language

imode sites can be inspected with ordinary Internet web browsers

imode imode is a packet-switched service users are charged per packet of

downloaded information imode uses packet-switched

technology for the wireless part of the communication.

The wired part of the communication is carried over TCP/IP.

imode DoCoMo has developed a data

transmission protocol specific to imode This protocol is used with the PDC-P

system The PDC-P network includes a mobile

message packet gateway (M-PGW) to handle conversions between the two protocol formats

Connection between the imode server and the Internet uses TCP/IP

imode

imode versus WAP Availability Different graphic capabilities Switching technique “always-on” capabilities Markup language used