Wireless Application Protocol

1
Wireless Application Protocol

• Kulesh Shanmugasundaram
• kulesh_at_photon.poly.edu

2
Introduction

• History of WAP
• Ericsson develop ITTP for VAS - 1995
• Unwired Planet develop HDML, HDTP - 1996
• Nokia develop Smart Messaging, TTML 1997
• WAP Forum formed in June 1997
• Table of Contents
• Architecture
• Protocol Stack
• Development
• Future of WAP

3
Architecture of WAP
WAP!
WAP!!
HTTP Request
Encoded Request
CGIScripts
User Agent
Encoders Decoders
content
Encoded Response
HTTP Response
Gateway(WAP Server)
Server (Web Server)
Clients(handheld device)
4
Architecture of WAP
5
Architecture of WAP
6
Limits
LimitedBandwidth
Im Popular!
LimitedDisplay
LimitedKeyboard
7
WAP Protocol Stack
Application Layer (WAE)
Other Services Applications
Session Layer (WSP)
Transaction Layer (WTP)
Security Layer (WTLS)
Transport Layer (WDP)
Bearers
iDEN
GSM
CDMA
CDPD
IS-136
8
WAP Protocol Stack

• Makes applications independent of bearers and
  other hardware
• External applications and services may access the
  layers directly
• Modified to allow for
• Lower Bandwidth (9.6kbps 14.4kbps)
• Network latency (6 10 seconds on SMS)
• Unreliable connections

9
Wireless Application Environment (WAE)

• A micro-browser environment containing
• Addressing Model (URL, URI)
• Wireless Markup Language (WML)
• WMLScript
• Content Formats WBMP, vCard, vCalendar
• WTA User Agent
• Handles wireless devices telephony functions

10
Wireless Session Protocol (WSP)

• A strip down version of HTTP/1.1 (B)
• Maintain session states
• Session suspend, resume (long-lived sessions)
• Facilitate reliable unreliable data push
• Protocol feature negotiation
• Header caching

11
Wireless Transaction Protocol (WTP)

• Three types of transactions
• Unreliable one-way requests (class 0)
• Reliable one-way requests (class 1)
• Reliable two-way request-reply (class 2)
• Reliability thru selective re-transmission
  delayed acks
• PDU concatenation
• Asynchronous transactions

12
Wireless Transport Layer Security (WTLS)

• WTLS is an optional layer
• Privacy thru encryption
• Data integrity thru MACs
• Authentication nonrepudiation thru digital
  certificates
• Compression
• Elliptic Curve Cryptography (ECC)
  http//www.certicom.com/

13
Wireless Datagram Protocol (WDP)

• Offers consistent services to upper layers and
  communicate transparently over one of the
  available bearer services.
• Global interoperability can be achieved using
  mediating gateways.
• IP IPLess bearers
• Use UDP for IP bearers (eg. CSD)
• Follow WAP Specs for others (GSM)
• Error handling done by WCMP

14
How limits are handled

• Low bandwidth
• WML contents are encoded
• WSP supports long-lived sessions
• WTP designed to minimize number of transactions
• High latency
• Asynchronous request/response model
• Client side programming using WMLScript
• WTA repositories
• Unreliable connection
• WSP supports long-lived sessions to resume
  efficiently
• Selective retransmission of segments by WTP

15
How limits are handled (cont)

• Small Display
• Decks and card interface
• Limited input facilities
• Decks and card makes inter-page navigation easier
• Limited memory CPU
• Binary encoding of WML contents saves memory
• Limited set of functionality of WMLScript
  libraries
• Limited battery power
• Minimizing bandwidth needs

16
What is in a client?

• WML
• A lightweight markup language, similar to HTML
  but optimized for hand-held devices
• WMLScript
• Similar to ECMA Script, enhanced with libraries
• Micro-browser
• WTA Libraries

17
What is in a WAP Server?
SNMP Java
Logging
Sub. DB
M A N A G E M E N T
BillingData
Subscriber Data
Encoders
ServerApplications
Context Manager
WSP
HTTP
WTP
WTLS
WDP/Adaptation
TCP/IP
Bearers
Internet/FW
18
What is in a WAP Server?

• WAP Server bridges the mobile hand-held device
  and rest of the world
• Usually it is the homepage of the browser in a
  handheld device
• WML/HTML Filters
• Two types of deployment strategies can be used
  (figures)

19
What does the web server do?

• Nothing unusual
• How to make your web server serve WAP contents.
  Define these MIME types
• Document type MIME type Typical extension
• Plain WML documents text/vnd.wap.wml .wml
• Wireless Bitmap Images image/vnd.wap.wbmp
  .wbmp
• Compiled WML documentsapplication/vnd.wap.wmlc
  .wmlc
• WMLScripts text/vnd.wap.wmlscript .wmls
• Compiled WML Scripts application/vnd.wap.wmlscrip
  tc .wmlsc
• You are ready to serve WAP contents!

20
WAP Development

• Development on the client side
• Limited memory, limited display, limited power,
  limited everything
• Most programming is done with WML, WMLScript,
  WTAI
• Some in ANSI C
• A Sample code

21
WML Howdy World!

• lt?xml version1.0?gt
• lt!DOCTYPE WML PUBLIC -//WAPFORUM//DTD WML
  1.1//ENhttp//www.wapforum.org/DTD/wml_1.1.xmlgt
• ltwmlgt
• ltcardgt
• ltpgt
• Howdy World!
• lt/pgt
• lt/cardgt
• lt/wmlgt

22
WAP Development

• Development on server side
• Most of the development is done at WAP Server
• Vendor dependent development tools
• Java Servlets, C/C PERL
• Usually APIs are provided
• Network operator may develop VAS on WTA Server

23
WAP Development

• What can we develop?
• Tetris, yay!
• Push technology at its best
• Access to your intranet
• Advanced telephony features using WTA
• Remotely control your house (MultiSens)
• Anything you wish!

24
Future of WAP

• Internet on a cell-phone
• Speech API
• Vendor independent telephony services
• Streaming media
• Multicasting
• Downloadable applications

25
Resources

• http//www.wapforum.com
• http//www.phone.com
• Nokia WAP Developer Forumhttp//www.forum.nokia.c
  om/developers/wap/
• The Independent WAP/WML FAQhttp//wap.colorline.n
  o/wap-faq/
• Yahoo!http//search.yahoo.com/bin/search?pWAP
• WAP Portalhttp//www.wapdrive.net/

26
The End

• The End