270 likes | 412 Views
Presentation on WAP. …Keerti Sharma August 2002. Agenda…. What is WAP ? Limitations of Internet for wireless applications WAP Architecture / protocol stack WAP Components / WML WAP brings Internet to hand-held devices Conclusion. WAP. What is WAP ?.
E N D
Presentation on WAP …Keerti Sharma August 2002
Agenda… • What is WAP ? • Limitations of Internet for wireless applications • WAP Architecture / protocol stack • WAP Components / WML • WAP brings Internet to hand-held devices • Conclusion WAP
What is WAP ? • WAP – The Wireless Application Protocol • Makes it possible to access the Internet via wireless devices such as mobile phones, PDAs etc. • Set of rules governing transmission/reception of data by wireless devices (e.g. mobile phones) set of rules
Limitations of Internet for Wireless Applications • Traditional Internet applications cannot run on mobile devices because of the following limitations: • Low bandwidth network • High Latency network • Limited connection stability • Small display size • Limited input facility • Limited memory • Limited processing power
Limitations of Internet (contd)… • Low bandwidth • Size of an HTML page, including graphics … 20 KB • Download time (56Kbps modem) … 3 s • Bandwidth of wireless network … 9.6Kbps • Download time for data on one page … 17 s • High latency • At the expiry of retransmission timer value, the TCP layer resends the packet of data • An average latency in a wireless network is around ½ s but can be as high as 10s • This can cause a lot of retransmission causing severe congestion
Limitations of Internet (contd)… • Limited connection stability • Small display size • Limited input facility • Limited memory • Limited processing power the WAP forum
. Client Web Server WAP Gateway WML CGI Scripts etc. WML Encoder WML-Script WSP/WTP HTTP WML Decks with WML-Script WMLScript Compiler WTAI Protocol Adapters Content Etc. WAP Architecture (contd)…
Client WAP Application Server WML WML Encoder Application Logic WML-Script WMLScript Compiler WSP/WTP WML Decks with WML-Script WTAI Protocol Adapters Content Etc. WAP Architecture (contd)… .
WAE - holds the tools that wireless Internet content developers use. WSP - determines whether a session between the device and the network will be connection-oriented or connectionless. WTP - acts like a traffic cop, keeping the data flowing in a logical and smooth manner. It also determines how to classify each transaction request: Reliable two way (WTP/C) Reliable one way (WTP/T) Unreliable one way (WTP/D) WTLS - provides many of the same security features found in the Transport Layer Security (TLS) part of TCP/IP. WDP - makes it easy to adapt the transport layer to a variety of bearers because all that needs to change is the information maintained at this level. WAP Architecture (contd)…
WAP Architecture (contd)… • In a real WAP solution, the main components include: • WAP Device • Bearer • WAP Gateway • Content • Content Server
WAP Components (contd)… • WAP Gateway • Encoder: converts WML to binarized WML • Adaptor: provides additional information through HTTP header • Translate HTTP requests to WSP. • Convert between SSL and WTLS • Convert transport protocols (TCP and WDP)
WAP Components (contd)… • WML (Wireless Markup Language) • An XML-based markup language that describes how WAP content is presented on a wireless terminal • Differs from HTML in the following • WML was specifically designed for wireless terminals with a target screen that is only a few lines long and about an inch wide. • WML is case sensitive, and all tags and attributes should be in lowercase. • Unlike HTML, WML is unforgiving of incorrectly nested tags. • WML doesn't assume that a keyboard or a mouse is available for user input. • Based on these differences, WML provides a smaller, telephony-aware set of tags that make it more appropriate than HTML for handheld wireless terminals.
WAP Components (contd)… • WML Contd… • Card metaphor • User interactions are split into cards • Navigation occurs between cards • Explicit inter-card navigation model • Hyperlinks • History • State management and variables • Reduce network traffic • Results in better caching
<WML> <CARD> <DO TYPE=“ACCEPT”> <GO URL=“#eCard”/> </DO Welcome! </CARD> <CARD NAME=“eCard”> <DO TYPE=“ACCEPT”> <GO URL=“/submit?N=$(N)&S=$(S)”/> </DO> Enter name: <INPUT KEY=“N”/> Choose speed: <SELECT KEY=“S”> <OPTION VALUE=“0”>Fast</OPTION> <OPTION VALUE=“1”>Slow</OPTION> <SELECT> </CARD> </WML> Navigation Card Variables Input Elements Example of WML … .
A Deck of Cards … <WML> <CARD> <DO TYPE="ACCEPT" LABEL="Next"> <GO URL="#card2"/> </DO> Acme Inc.<BR/>Directory </CARD> <CARD NAME="card2"> <DO TYPE="ACCEPT"> <GO URL="?send=$type"/> </DO> Services <SELECT KEY="type"> <OPTION VALUE="em">Email</OPTION> <OPTION VALUE="ph">Phone</OPTION> <OPTION VALUE="fx">Fax</OPTION> </SELECT> </CARD> </WML> . Acme Inc. Directory _____________ Next Services 1>Email 2 Phone ____________ OK
WAP brings Internet to Hand- held Devices • WAP handles limited bandwidth • Minimizes traffic over wireless interface • WSP layer, too, is binary encoded • WTP is not only designed to minimize amount of data but also number of transactions • WAP handles high latency • WAE uses scripting to avoid round trip delays, e.g. by validating user input locally • WTAI environment introduces a repository to hold services that should be started in response to an event in mobile network, e.g. incoming call.
WAP brings (contd)… • WAP handles less stable connections • The sessions supported by WSP are assumed to be long-lived. • WTP layer has been kept very simple compared to TCP • WTP supports selective retransmission of data • WAP handles small displays • WML structures its documents in ‘Decks & Cards’ • When an application is executed, user navigates through a series of cards
WAP brings (contd)… • WAP handles limited input facilities • The WML elements can be easily be implemented without much input required from the key-board • Deck & Cards model requires minimal navigation between pages • Soft buttons or user-definable keys are also supported by WML • WAP handles limited memory and CPU • Defining a light weight protocol stack • Limited functionality provided by WML & WMLScript • Binary encoding of WML & WMLScript
Conclusion • WAP provides a “microbrowser” optimized for wireless devices • Requires minimal RAM, ROM, Display, CPU and keys • WAP Offers Bearer Independence • Allows Applications developed once to work across all networks • Protects the Carrier’s investment in wireless data as networks evolve • Enables Mobile Device Manufacturers to use common code across products • WAP Offers Device Independence • Allows applications developed once to work across devices from small handsets to powerful PDAs • Promotes consistent user experience across all of a carrier’s handset offerings • Encourages a wealth of applications for handset manufacturers
Some WAP applications • Financial services • Banking • Bill-paying • Stock trading • Funds transfers • Travel services • Schedules and rescheduling • Reservations • Location-based services • Real-time traffic reporting • Event/restaurant recommendation • Highly customized ads • Instant messaging-type “buddy” location • Enterprise solutions • Email access • Database access • A “global intranet” • Information updates “pushed” to WAP devices
Some known WAP Services • 123Jump (http://www.123jump.com) A selection of stock data & news, all via WAP • Ajaxo (http://www.ajaxo.com) A WAP service for wireless stock trading from any WAP enabled device • 2PL WorldWide Hotel Guide (http://wap.2pl.com) A hotel guide, accessible in multiple languages via WAP enabled device • Traffic Maps (http://www.webraska.com) A French service that monitors and shows latest traffic news via maps
WAP demo • http://www.w3schools.com/wap/wap_demo.asp
Next presentation will cover … • WAP 2.0 • Integrating JAVA with WAP • Push Technology in WAP • Using WAP with Bluetooth
References 1. http://www.wapforum.org http://www.mobileinfo.com/WAP/components.htm http://wap.sonyericsson.com/ http://www.nokia.com/phones/9110/app.html http://www.iec.org/online/tutorials/wap/ http://www.wapaka.com/wapaka/default.asp http://www.ericsson.com/about/publications/review/2001_04/files/2001043.pdf http://www.btob.barnesandnoble.com/offers/wapgap.asp?btob=Y http://www.w3schools.com/wap/wap_pages.asp
References 2. • Professional WAP • WAP – A Beginner’s Guide by Dale Bulbrook • Wireless Crash Course by Bedell • Cracking the Code – WAP, Bluetooth & 3G Programming • WAP Integrationby Vujosevic & Laberge • WAP 2.0 Development by Tull