Wireless Application Protocol - Mobile Communications - Lecture Slides, Slides of Mobile Communication Systems

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Wireless Application Protocol

Outline

• Mobile applications

• How are mobile/wireless environments different?

• What is WAP?

• WAP Architecture

• WAE (WML/WMLScript)

• WTA Framework

• WAP Push Services

• WAP Protocol Stack

• Hype v/s Reality

• References and Resources

Mobile Applications - 2

• Web access

• outdoor Internet access
• intelligent travel guide with up-to-date location

dependent information

• Information services

• push: stock quotes; pull: nearest cash ATM

• Disconnected operations

• file-system caching for off-line work
• mobile agents, e.g., shopping

• Entertainment

• games, etc

Variability of the Mobile Environment

Connectivity

• connected
• semi-connected (asymmetric)
• weakly connected
• disconnected

Mobile Device Capability

• form factor
• GUI
• multimedia
• real-time multimedia

Mobility

• stationary
• nomadic (pedestrian speed)
• mobile (vehicular speed)
• roaming (mobile across networks)

System Support for Mobile WWW

• Enhanced browsers

• client-aware support for mobility

• Proxies

• Client proxy: pre-fetching, caching, off-line use
• Network proxy: adaptive content transformation for

connections

• Client and network proxy

• Enhanced servers

• server-aware support for mobility
• serve the content in multiple ways, depending on client

capabilities

• New protocols/languages

• WAP/WML

Wireless Application Protocol (WAP)

• Empowers mobile users with wireless devices to easily access and

interact with information and services.

• A “standard” created by wireless and Internet companies to enable

Internet access from a cellular phone

• wapforum.org:
  • co-founded by Ericsson, Motorola, Nokia, Phone.com
  • 450 members in 2000, comprise of Handset manufacturers, Wireless service providers, ISPs, Software companies in the wireless industry
  • Goals
    • deliver Internet services to mobile devices
    • enable applications to scale across a variety of transport options and device types
    • independence from wireless network standards
    • GSM, CDMA IS-95, TDMA IS-136, 3G systems (UMTS, W-CDMA)

Internet Model

HTML

HTTP

TLS/SSL

TCP/IP

Web Server

Content

CGI Scripts etc.

WML Decks with WML-Script

WAP Gateway

WML Encoder

WMLScript Compiler

Protocol Adapters

Client

WML

WML- Script

WTAI

Etc.

WSP/WTP HTTP

WAP Architecture

Source:Docsity.com WAP Forum

WAP Architecture

• Another look

Key Components

• Origin/Web Server
• WAP Gateway/Proxy
• WAP Protocol Stack
• Micro Browser
• WML/WML Script
• Transcoders
• WTA

Source:Docsity.com WAP Forum

WAP: Network Elements

fixed network wireless network

WAP proxy

WTA server

filter/ WAP web proxy server

filter

PSTN

Internet

Binary WML: binary file format for clients

Binary WML

Binary WML

Binary WML

HTML

HTML

HTML WML

HTML^ WML

Source: SchillerDocsity.com

WAP Stack

MicroBrowser (WML, WMLScript, WTA, WTAI)

Runs on top of WDP Provided lightweight X-oriented service

• Unreliable 1-way request
• Reliable 1-way/2-way req./response

Lightweight SSL Uses WIM/PKI-Cards

Datagram service on different bearers Convergence between bearer services

Different Wireless Tech.

Source:Docsity.com WAP Forum

WAP Stack

• WAE (Wireless Application Environment):
  • Architecture: application model, browser, gateway, server
  • WML: XML-Syntax, based on card stacks, variables, ...
  • WTA: telephone services, such as call control, phone book etc.
• WSP (Wireless Session Protocol):
  • Provides HTTP 1.1 functionality
  • Supports session management, security, etc.
• WTP (Wireless Transaction Protocol):
  • Provides reliable message transfer mechanisms
  • Based on ideas from TCP/RPC
• WTLS (Wireless Transport Layer Security):
  • Provides data integrity, privacy, authentication functions
  • Based on ideas from TLS/SSL
• WDP (Wireless Datagram Protocol):
  • Provides transport layer functions
  • Based on ideas from UDP

Content encoding, optimized for low-bandwidth channels, simple devices

WAP: “Killer” Applications

• Location-based services
  • Real-time traffic reporting, Event/restaurant recommendation
• Enterprise solutions
  • Email access, Database access, “global” intranet access
  • Information updates “pushed” to WAP devices
• Financial services
  • Banking, Bill-paying, Stock trading, Funds transfers
• Travel services
  • Schedules and rescheduling, Reservations
• Gaming and Entertainment
  • Online, real-time, multi-player games
  • Downloadable horoscopes, cartoons, quotes, advice
• M-Commerce
  • Shopping on the go
  • Instant comparison shopping
  • Location-based special offers and sales

Wireless Application Environment

(WAE)

• Goals
  • device and network independent application environment
  • for low-bandwidth, wireless devices
  • considerations of slow links, limited memory, low computing power, small display, simple user interface (compared to desktops)
  • integrated Internet/WWW programming model
  • high interoperability