WAP- Wireless Application Protocol Mobile Applications - 1 Vehicles transmission of news, road condition etc ad-hoc network with near vehicles to prevent accidents Emergencies early transmission of patient data to the hospital ad-hoc network in case of earthquakes, cyclones military... Traveling salesmen direct access to central customer files consistent databases for all agents mobile office 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 Variability of the Mobile Environment Mobility stationary nomadic (pedestrian speed) mobile (vehicular speed) roaming (mobile across networks) Disconnected operations file-system caching for off-line work mobile agents, e.g., shopping Entertainment games, etc Mobile Device Capability form factor GUI multimedia real-time multimedia Connectivity connected semi-connected (asymmetric) weakly connected disconnected 1
World Wide Web and Mobility HTTP/HTML have not been designed for mobile applications/devices HTTP 1.0 characteristics designed for large bandwidth, low delay stateless, client/server, request/response communication connection oriented, one connection per request TCP 3-way handshake, DNS lookup overheads big protocol headers, uncompressed content transfer primitive caching (often disabled, dynamic objects) security problems (using SSL/TLS with proxies) HTML characteristics designed for computers with high performance, color high-resolution display, mouse, hard disk typically, web pages optimized for design, not for communication; ignore end-system characteristics 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 Overview WAP Introduction WAP architecture requirements Architecture overview World-wide web model WAP model Components of WAP architecture Sample Configuration of WAP technology Usage, Advantages & Disadvantages of WAP Summary WAP- Wireless Application Protocol An open, global specification that empowers mobile users with wireless devices to easily access and interact with internet information and services instantly. The wireless industry came up with the idea of WAP. The point of this standard was to show internet contents on wireless clients, like mobile phones. 2
WAP stands for Wireless Application Protocol o WAP is an application communication protocol o WAP is used to access services and information o WAP is inherited from Internet standards o WAP is for handheld devices such as mobile phones o WAP is a protocol designed for micro browsers o WAP enables the creating of web applications for mobile devices. o WAP uses the mark-up language WML (not HTML) WML is defined as an XML 1.0 application The WAP specifications continue to be developed by contributing members, who, through interoperability testing, have brought WAP into the limelight of the mobile data marketplace with fully functional WAP enabled devices as shown below: The basic AIM of WAP is to provide a web-like experience on small portable devices - like mobile phones and PDAs. 3
Purpose of WAP To enable easy, fast delivery of relevant information and services to mobile users. Type of devices that use WAP Handheld digital wireless devices such as mobile phones, pagers, two-way radios, smart phones and communicators -- from low-end to high-end. WAP works with most Wireless networks such as: CDPD, CDMA, GSM, PDC, PHS, TDMA, FLEX, ReFLEX, iden, TETRA, DECT, DataTAC, Mobitex. Operating systems that are compatible with WAP WAP is a communications protocol and an application environment. WAP is independent of OS that means WAP can be implemented on any OS. It can be built on any operating system including Palm OS, EPOC 32, Windows CE, FLEXOS, OS/9, Java OS, etc. It provides service interoperability even between different device families. WAP Architecture Requirements Leverage existing standards whenever possible Define a layered, scaleable and extensible architecture Support as many wireless networks as possible Optimize for narrow-band bearers with high latency WAP Architecture Requirements (Contd.) Optimize for efficient use of device resources Provide support for secure applications and communication 4
Architecture Overview WWW programming model is optimized and extended to match characteristics of the wireless environment Utilizes proxy technology to connect between the wireless domain and WWW WAP: Main Features Browser Micro browser, similar to existing web browsers Markup language Similar to HTML, adapted to mobile devices Script language Similar to Javascript, adapted to mobile devices Gateway Transition from wireless to wired world Server WAP/Origin server, similar to existing web servers Protocol layers Transport layer, security layer, session layer etc. Telephony application interface Access to telephony functions Internet Model Client Web Browser Request (URL) Response (Content) Web Server CGI, Scripts, Etc. Content HTML HTTP TLS/SSL TCP/IP Client WAE User Agent WAP Programming Model Encoded Request Encoded Response Gateway Encoders And Decoders Request (URL) Response (Content) Web Server CGI, Scripts, Etc. Content 5
WML Decks with WML-Script WAP Architecture WAP Device - Is used to access WAP applications and content. It might be a PDA, handheld computer. Client WML WML- Script WTAI Etc. WSP/WTP WAP Gateway WML Encoder WMLScript Compiler Protocol Adapters HTTP Web Server CGI Scripts etc. Content WAP Client - Entity that receives content from Internet via a WAP Gateway. This is usually the WAP Browser. WAP Content/Origin/Application Server - Element in the network where the information or web/wap applications resides. Source: WAP Forum WAP Proxy - Acts both as a client and as a server in the network.typically has Protocol gateway : translates requests from the WAP protocol stack to WWW protocol stack Content encoders and decoders : translate WAP content into compact encoded formats to reduce the size of data over the network It allows content and applications to be hosted on standard WWW servers and developed using proven WWW technologies such as CGI scripting WAP Gateway - Intermediary element used to connect two different types of network. It receives request directly from the clients as if it actually were the origin server that clients want to receive the information form. The clients are usually unaware that they are speaking to the Gateway. WAP Browser Software running on the WAP device that interprets the WAP content arriving from the internet and decides how to display it on WAP device. 6
WML WML Wireless Markup Language formerly called HDML (Handheld Devices Markup Language) Is a tag language that allows the text portions of Web Pages to be presented on cellular phones and Personal Digital Assistants (PDAs) via wireless access. WML is used for delivering data to WAP devices, and is HTML- like in its appearance. An alternative to WML is I-Mode s chtml language. Web Server HTML WAP Network Example WML HTML Filter WML WAP Proxy WTA Server Wireless Network WAP Client WWW Protocol Stack Components of WAP Architecture HTML Java Script HTTP TLS - SSL Application Layer (WAE) Session Layer (WSP) Transaction Layer (WTP) Security Layer (WTLS) Transport Layer (WDP) Other Services And Applications TCP/IP UDP/IP Bearers : GSM CDMA PHS IS-136 CDPD PDC-P FLEX Etc 7
Wireless Application Environment (WAE) General-purpose application environment based on a combination of WWW and mobile telephony technologies. It defines the user interface on the phone. It contains WML and WTA (Wireless Telephony Application). Primary objective interoperable environment. Wireless Application Environment (Contd.) WAE includes a micro-browser (Client software designed to overcome challenges of mobile handheld devices that enables wireless access to services such as Internet information in combination with a suitable network) server environment which provides WML WML script WTA Content formats Wireless Session Protocol (WSP) The WAP session protocol (WSP) layer provides a lightweight session layer to allow efficient exchange of data between applications. Application layer with a consistent interface for two session services Connection-oriented service that operates above the transaction layer protocol (WTP) Connectionless service that operates above a secure or non-secure datagram service (WDP) Optimized for low-bandwidth bearer networks with long latency Wireless Transaction Protocol (WTP)» Runs on top of a datagram service The WAP transaction protocol (WTP) layer provides transaction support, adding reliability to the datagram service provided by WDP. Light weight transaction-oriented protocol Three classes of transaction services Unreliable one-way requests Reliable one-way requests Reliable two-way request-reply transactions 8
Wireless Transport Layer Security (WTLS) Based on industry-standard Transport Layer Security (TLS) protocol Optimized for use over narrow-band communication channels Features: Data integrity Privacy Authentication Denial-of-service protection Wireless Datagram Protocol (WDP) The WAP datagram protocol (WDP) is the Transport layer that sends and receives messages via any available bearer network, including SMS, USSD, CSD, CDPD, IS 136 packet data, and GPRS. Operates above the data capable bearer services supported by various network types. Provides a common interface to the upper layer protocols and hence they function independent of the underlying wireless network. Bearers Differing levels of quality of service with respect to throughput, error rate, and delays WAP protocols are designed to compensate for or tolerate these varying levels of service WDP specification lists the bearers that are supported and techniques used to allow WAP protocols to run over each bearer USAGE - Corporate Applications: Sales force automation where sales people use their WAP enabled handsets to get instant, direct access to the latest pricing, latest news, competitive information any time, anywhere. - Online Services: Banking: Users can get their current balance, transfer funds between accounts and receive fax of a ministatement. Electronic Commerce: Subscribers can use their handset just like their PC to purchase products and services over the Web. 9
- Tele services Prepaid Services: With a WAP-enabled phone, prepaid subscribers can see their current balance with the press of a button. By pressing another button, they can also recharge their account by entering a credit card or voucher number into the handset. - Personal Productivity Email: Using WAP users can keep track of their email right from their handset. - Others include: - Interactive Chat - Auctions - Games The ADVANTAGES that WAP can offer over these other methods are the following: open standard, vendor independent network-standard independent transport mechanism optimized for wireless data bearers application downloaded from the server, enabling fast service creation and introduction, as opposed to embedded software DISADVANTAGES of WAP Small screens: For web phones, there's an incredibly small viewing area; palmtops are barely better. Speed of access: All devices have slow access. Limited or fragmented availability: Wireless web access is sporadic in many areas and entirely unavailable in other areas. Price: Many technology limitations are being addressed by higher-end devices and services. But the entry price for a good wireless web palmtop with decent display, keyboard, and speed is easily $700 to $900, not including monthly access. Lack of user habit: It takes some patience and overcoming the learning curve to get the hang of it -- connecting, putting in an address, typing. Users just aren't used to the idea and protocol yet. How it works 1. The user selects an option on their mobile device that has a URL with WML content assigned to it. 2. The phone sends the URL request via the phone network to a WAP gateway, using the binary encoded WAP protocol. 3. The gateway translates this WAP request into a conventional HTTP request for the specified URL, and sends it on to the Internet. 4. The appropriate Web server picks up the HTTP request. 5. The server processes the request, just as it would be any other request. If the URL refers to a static WML file, the server delivers it. If a CGI script is requested, it is processed and the content returned as usual. 10
6. The Web server adds the HTTP header to the WML content and returns it to the gateway. 7. The WAP gateway compiles the WML into binary form. 8. The gateway then sends the WML response back to the phone. 9. The phone receives the WML via the WAP protocol. 10. The micro-browser processes the WML and displays the content on the screen. WAP Infrastructure WWW programming Model WAP programming Model Wap gatewy protocolstack WAP Profile -OTP WAP profile WAP browser requires a set of parameters to build a connection to an internet application. These parameters are stored in a WAP profile on mobile client <like IP connections parameters stored in Browser(IE, Mozilla,..) profile> No. of profiles can be stored in a mobile phone is limited to 3 or 5.in some case with a fixed one profile. Very restricted to one WAP gateway of their Provider. WAP Profile elements Homepage (URL) Connection type( packet/ckt) Connection security(wtls-on/off) Bearer (service used for service if sms HSCSD/GSM) Dial up number(extn of dail in server) IP address(gateway) Authentication Type (any security certificate is used for cleint auth.en, set normal or secure) Data call type (signalling bw phone and dail in server,analog sig. < ISDN.. But in some countries need to use Analog phone lines..) Data call speed (9.6 /14.4 ) User name Password 11
WAP security issues End End Security Missing secure authentication Unauthenticated OTP Missing public key Infrastructure WAP provides security with the help of WTLS, which involves Diffie Hellman key exchange, Elliptic curve cryptography. Privacy through DES - Data Encryption Standard IDEA - International Data Encryption Algorithm Special features: WIM -WAP Identification Module WPKI- WAP Public key Infrastructure Session Security: 12
Redirection to secure WAP gateway is another method to solve the security issue The end to end security is achieved through TLS What is WML? WML stands for Wireless Markup Language. It is a mark-up language inherited from HTML, but WML is based on XML, so it is much stricter than HTML. WML is used to create pages that can be displayed in a WAP browser. Pages in WML are called DECKS. Decks are constructed as a set of CARDS *An application can transmit multiple pages(cards) simultaneously in a single transmission unit called Deck. *Can display a new page after some time using timer *Unlike HTML,it is stateful..so it can preserve content of variables between different WML pages. What is WMLScript? WML uses WMLScript to run simple code on the client. WMLScript is a light JavaScript language. However, WML scripts are not embedded in the WML pages. WML pages only contains references to script URLs. WML scripts need to be compiled into byte code on a server before they can run in a WAP browser. 13
Standard Libraries available in WML. Lang library(provides functions for WML script such as min,max,random) Float library(floating point functions like floor,round,pow.) String library(string manipulating functions substring., length) URL library(handling absolute and relative URLs) WML Browser library(functions for manipulating associated WML context loading a new page update display..also contains setvar to set value for WML variable.) Dialogs Library (user interface fn. Prompt for ip. Or confirm an action.) Binary encoded format to reduce no. of bytes transferred. WML decks and Scripts are encoded Use WBMP compressed WML source (210 bytes ) => 44 bytes of WBXML Typical value of WML deck 1400-2048 bytes.. Pagination : deck fragmentation. <?xml version="1.0"?> <!DOCTYPE wml PUBLIC "-//WAPFORUM//DTD WML 1.1//EN" "http://www.wapforum.org/dtd/wml_1.1.xml"> <wml> <card> <p> Hell </p> </card> </wml> <?xml version="1.0"?> <!DOCTYPE wml PUBLIC "- //WAPFORUM//DTD WML 1.1//EN" "http://www.wapforum.org/dtd/wml_1.1. xml"> <wml> <card><p> Hell how <br/> bye <br/> no <br/> good <br/> hell <br/> <br/> bad </p> </card> </wml> 14
<?xml version="1.0"?> <!DOCTYPE wml PUBLIC "-//WAPFORUM//DTD WML 1.1//EN" "http://www.wapforum.org/dtd/wml_1.1.xml"> <wml> <card> <p align="left"> No </p> <p align="center"> Hi </p> <p align="right"> Bye </p> </card> </wml> <?xml version="1.0"?> <!DOCTYPE wml PUBLIC "-//WAPFORUM//DTD WML 1.1//EN" "http://www.wapforum.org/dtd/wml_1.1.xml"> <wml> <card> <p> Hi <table title="bye" columns="2" align="right"> <tr><td>aa</td><td>bbbb</td></tr> <tr><td>c</td><td>dd</td></tr> </table> </p> </card> </wml> <?xml version="1.0"?> <!DOCTYPE wml PUBLIC "-//WAPFORUM//DTD WML 1.1//EN" "http://www.wapforum.org/dtd/wml_1.1.xml"> <wml> <card title='no' id="a1"> <p> Hi <a href="#a2"> Good </a> </p> </card> <card id="a2"> <p > Bye </p> </card> </wml> 15
16
PAP Carries XML formatted doc. Over internet PAP offers push submission: sends sms to mobile device Confirmation Notification: sent to initiator When delivered push cancellation: initiator to PPG,when previous submitted push should be cancelled Status query : response contains the status of a submission Client capabilities: query req., returns the capabilities of mobile device.. Push OTP: layer for transmitting push msg over the WSP.. Responsible for exchanging content b.w. user agent and PPG Summary WAP provides a markup language and a transport protocol that open the possibilities of the wireless environment and give players from all levels of the industry the opportunity to access an untapped market that is still in its infancy. The bearer-independent nature of WAP has proved to be a longawaited breath of fresh air for an industry riddled with multiple proprietary standards that have suffocated the advent of a new wave of mobile-internet communications. WAP is an enabling technology that, through gateway infrastructure deployed in mobile operator's network, will bridge the gap between the mobile world and the Internet, bringing sophisticated solutions to mobile users, independent of the bearer and network. Backed by 75 percent of the companies behind the world's mobile telephone market and the huge development potential of WAP, the future for WAP looks bright. Websites: References Books: Beginning WAP Wrox Publications Dynamic WAP Application Development- Manning Publications, Inc 17