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Wireless LAN, Mobile Internet Connectivity, and Personal Area Network

Lesson 03Wireless Application Protocol (WAP1.1

and 2.0) Architecture

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Wireless Application Protocol

• Offers open development platform for applications

• WAP 2.0 and WAP 1.1

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Hypertext Transfer Protocol (HTTP)

• Hypertext means a text which can embed the links to any other text, image, audio clip, or video clip through the URLs and hence enable navigation through these URLs

• HTTP transfers a hypertext, text, data, or voice tagged using HTML

• Similarly, WAP transfers a text written in WML (wireless markup language)

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WAP 1.1

• Two sets of software1. WAE (wireless application environment)2. WAE services

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Wireless Application Environment (WAE) 1.1

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WAE in WAP 1.1

• WML [Refer Lesson 5 for details]• WBXML• WTA• WMLScript• Data formats─ vCard 2.1, vCalendar 1.0,

address book, and pictures (jpg, gif, …)• User agent

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WBXML

• WAP 1.1 provides for communication of client with gateway or proxy using WBXML

• XML and WML page document are not compact

• WBXML specification in binary representation so that XML or XML-based language─ transmitted and received in compact format

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WBXML

• A binary number can represent a tag in place of characters

• Another binary number can represent an attribute in place of characters

• For example, attribute ID needs two characters

• It is represented by a single byte• Attribute title needs five characters• It is also represented by a single byte

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Wireless Telephony Application (WTA ) Protocol

• Call set up• call accept• call forwarding• caller line ID• connected line ID• closed user group• multiparty groupings

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Wireless Telephony Application (WTA ) Protocol

• call waiting• call barring• operator restrictions• call charge advice• contacts entry in phone book• call hold

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Wireless Telephony Application (WTA ) Protocol

• conferencing• ring tones• speed dial• telephone/fax• SMS up to 160 characters• emergency number, MMSgif, jpg, wbmp,

teletext, and videotext access

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WATI (WTA interface)

• WATI provides the interfaces the features using WML browser

• A WTA URI can be wtai://wap.mcard: followed by a telephone number

• Identical to port number specifications provided in the URL

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WTA URI

• Example: wtai://wap.mcard: followed by a telephone number

• Identical to port number specifications provided in the URL

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Wireless Telephony Application (WTA ) Server

• Server can push the WMLScript or deck contents

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Wireless Telephony Application (WTA ) event handler

• A WTA event handler can handle WTA events

• Example of an event─ change in data-field content

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Wireless Telephony Application (WTA )

• A persistent storage interface helps in storing the data on device when the content is modified. WTA also provides security interface

• Only authorised gateway or proxy can access the data at the server

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User Agent

• Software used by the user to give input using VUI (voice user interface)

• GUI (graphic user interface) • To interact with mini browser (browser with

limited screen size)• Executes the WMLScript at the client and

displays the results• Displays the WML decks received as

response from the server

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User Agent Profile

• Provides small screen device characteristics, font, and display capabilities

• Enhances the input capabilities, for example, the use of T9 keypad, stylus, and touch screen is enabled

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Data formats for data displayed on a mobile device

• vCard 2.1 is the format for visiting card• vCalendar 1.0 is the format for calendar• Also a mobile device provides pictogram

which is a small picture of very low resolution that cannot be split and can be placed along with the text

• Pictogram used for displaying logo

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WAE 2.0

• WAE 1.1• XHTML-MP • HTTP• HTML Browser

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WAP 2.0

• Wireless protocol for synchronization of WAP client computers and WAP or HTTP server

• Derived from the architecture of the synchronization between HTTP client (browser) and the HTTP server (web server) in wired Internet

• WAP 2.0 has backward compatibility and supports WAP 1.1 devices

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WAP2.0

• Wireless Session layers and Wireless Transport protocol layers not required in case of WAE XHTML-MP or HTML

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WAP 1.1 and WAP 2.0 Protocol Layers

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Synchronization in WAP 1.1 and WAP 2.0

• Remote service provider pre-configuring of the device for provisioning of services

• Used for data synchronization between server and mobile devices

• WAP 2.0 uses SyncML for Remote service provider pre-configuring of the device for provisioning of services

• WAP 2.0 uses SyncML for data synchronization between server and mobile devices

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WAP 1.1 Gateway

• Required for protocol conversions between two endsmobile client device and HTTP server

• Required for iWMLScript (Internet WML script) compilation into CGI script which runs at the HTTP server to get HTML response which is sent to the client application

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WAP 1.1 Gateway

• Gateway converts WAE 1.1, WSP, WTP, WTLS, and UDP layers encoded data packets into the HTTP, TLS (in HTTPS), and UDP layers encoded data packets when the device transmits data to server

• Does decoding when the server sends data to client through the gateway

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WAP 2.0

• WAP 1.1 gateway encoders and decoders not required in WAP 2.0

• A WAP gateway connects WAP client to HTTP servers

• HTTP server serves the websites on the Internet

• HTTP layer in TCP/IP protocol suite acts as application layer protocol when connecting to Internet on a wired network

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WAP Push-Proxy Gateway

• WAP 2.0 uses XHTML-MP (Extensible Hypertext Markup Language Mobile Profile) in place of WML

• Therefore encoding and compilation is not required and only a WAP 2.0 proxy suffices

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Architecture for communication between a WAP client and HTTP

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Running of application in a Mobile device WAE

• A WML card containing a client-request is transmitted and is decoded at the gateway

• After decoding, the gateway communicates the request to the server in HTML format

• The server generates an HTML response by employing the method(s) which run at the server

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Running of application in a Mobile device WAE

• The response is encoded in WML form at the gateway

• The gateway transmits the WML response to mobile-device client which runs an application after parsing the WML

• The application uses the methods which run at the client

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WAP Push-Proxy Gateway

• HTTP web servers function in pull mode• That is, an HTTP client application sends

a request to the server and the HTTP server sends the response

• Mobile device applications require data dissemination by server in push mode, pull mode, and push-pull hybrid mode

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WAP Push-Proxy Gateway

• A WAP 2.0 proxy is required for pull mode• A push-proxy gateway is used to

exchange data packets between a mobile device through wired Internet and Web servers. The role of WAP 2.0 gateway is restricted to provisioning for push and pull mode services from the servers

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WAP 2.0

• Have three important features over WAP 1.1

1. SyncML synchronization2. WAP push service3. MMS service

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SyncML Synchronization in WAP 2.0

• Remote service provider pre-configuring of the device for provisioning of services

• Used for data synchronization between server and mobile devices

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WAP 1.1 architecture

• Does not provide HTTP-TLS-TCP-IP layers at the WAP client for interacting with the WAP gateway

• TLS (transport layer security)─ a security protocol

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WAP 1.1

• WAP gateway, therefore, uses a decoder for sending request to web HTTP server and an encoder for sending response to WAP client

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WAP gateway

• WAP gateway provides access to the wireless and wired networks and also builds caches due to frequent disconnections in the wireless environment

• Ensures security in wireless and wired networks

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WAP gateway

• An HTTP server environment provides only pull mode service but WAP gateway has provisions for both push and pull mode services from the servers

• Pull mode means client sends a request and pulls the data from server as a response

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Summary

• WAP 2.0 and WAP 1.1 application development platforms

• WAP transfers a text written in WML (wireless markup language)

• WAP gateway required for protocol conversions and iWMLScript (Internet WML script) compilation into CGI script

• WBXML…

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…Summary

• WTA• User Agent• Special data format for WAP • WAP 2.0 uses XHTML-MP (Extensible

Hypertext Markup Language Mobile Profile) in place of WML

• Encoding and compilation not required and only a WAP 2.0 proxy suffices

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End of Lesson 03Wireless Application Protocol (WAP1.1

and 2.0) Architecture