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WAP Overview

WAP Overview. Amarnath Chitti. Introduction. What is WAP ? Wireless Application Protocol What is its Purpose ? Defines standards for wireless application environment (WAE) Who coordinates the WAP standard meetings? WAP forum(www.wapforum.org) not IETF

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WAP Overview

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  1. WAP Overview Amarnath Chitti "CSC8530 Distributed Systems", Summer 2002

  2. Introduction • What is WAP ? • Wireless Application Protocol • What is its Purpose ? • Defines standards for wireless application environment (WAE) • Who coordinates the WAP standard meetings? • WAP forum(www.wapforum.org) not IETF • What part of OSI does WAP standards address? • Session, Presentation and Application • What are the main ingredients of WAP? • WDP: WAP Datagram Protocol • WTLS: Wireless Transport Layer Security • WTP: Wireless Transaction Protocol • WSP: WAP Session Protocol • WML: Wireless Markup Language "CSC8530 Distributed Systems", Summer 2002

  3. Introduction (contd.) • WAP Applications: • Wireless Web hosting • Location Based Services with WAP Push Technology • Secure Mobile Connectivity to enterprise networks • Example: Nokia Activ Server 2.1 • Mobile Financial Services with Nokia Activ Server • Mobile Reservation systems "CSC8530 Distributed Systems", Summer 2002

  4. Introduction (contd..) WAP Overview Diagram: "CSC8530 Distributed Systems", Summer 2002

  5. Introduction (contd..) Protocol Diagram at a WAP Gateway: "CSC8530 Distributed Systems", Summer 2002

  6. WAP with reference to Distributed Systems • WAP needs to operate across different Air Interface Technologies. Example: CDMA, IS 95, IS 136 etc. • DNS lookups of the servers by the WAP Gateway • WAP gateway contacting different Application Servers based on Client Requests. "CSC8530 Distributed Systems", Summer 2002

  7. WAP with reference to Distributed Systems (contd.) WAP Gateway MSC MSC GSM IS 136 "CSC8530 Distributed Systems", Summer 2002

  8. Typical WAP Network redrawn from WAP Architecture Document "CSC8530 Distributed Systems", Summer 2002

  9. WAP interface to various Air Interface Technologies "CSC8530 Distributed Systems", Summer 2002

  10. Brief Description of WAP stack • Elements of WAP Stack compared Internet Stack • WML vs. HTML • WSP vs. HTTP • WTP vs. TCP • WTLS vs. TLS • WDP vs. UDP • WCMP vs. ICMP "CSC8530 Distributed Systems", Summer 2002

  11. WML vs. HTML • WML: Wireless Markup Language • WML is an XML based markup language. • XML and HTML are based on Structured Generalized Markup Language (SGML). • To support WML requirements, W3C created XHTML standard. • WAP 2.0 uses XHTML. • Freeware available for converting HTML pages to XHTML/XML pages. • Example: http://www.vbxml.com/wap/articles/htmlwml/default.asp "CSC8530 Distributed Systems", Summer 2002

  12. WSP vs. HTTP • WSP: Wireless Session Protocol • WSP defines two protocols: • one provides connection-mode session services over a transaction service • To provide non-confirmed, connectionless services over a datagram transport service. • WSP recodes existing RFC-822 style request and response messages in their own binary tokenization format • WSP cannot support IETF's Proposed Standard for distributed authoring over HTTP (WebDAV) • WSP does content-negotiation not by Content-Type:, but with explicitly deprecated User-Agent: • WAP 2.0 adopts HTTP/1.1 as a session layer protocol. "CSC8530 Distributed Systems", Summer 2002

  13. WTP vs. TCP • WTP: Wireless Transaction Protocol • WTP tries to solve a mix of transport- and application-layer problems. • WTP optionally offers segmentation and re-assembly and selective acks. (WDP ??) • WTP offers three application message models: • Class 0: Unreliable invoke message with no result message • Class 1: Reliable invoke message with no result message • Class 2: Reliable invoke message with one reliable result message • WTP is the heart of an independent WAP Gateway server project, such as APiON's. • WTP is the lowest layer the microbrowser absolutely requires • WAP 2.0 features TCP/IP for wireless networks supporting Data over IP. "CSC8530 Distributed Systems", Summer 2002

  14. WTLS vs. TLS • WTLS: Wireless Transport Layer Security • WTLS Requirements: • Both datagram and connection oriented transport layer protocols must be supported • To cope with long round-trip times of wireless networks • Support limited bandwidth of some bearer networks • Match the processing power of mobile terminals • Match the memory requirements of mobile terminals "CSC8530 Distributed Systems", Summer 2002

  15. WTLS vs. TLS (contd.) • TCP/IP stack offers security at the packet- and transport-layers with two technologies • Ipsec for unreliable datagram transport (UDP) • TLS for reliable transport (TCP) • WTLS applies TLS to both individual datagrams and socket connections • WTLS defines three levels of security capabilities; only Class 1 is mandatory-to-implement. "CSC8530 Distributed Systems", Summer 2002

  16. WTLS vs. TLS (contd.) "CSC8530 Distributed Systems", Summer 2002

  17. WTLS vs. TLS (contd.) • WTLS specifies use of Certicom's elliptic curve public key encryption (mentioned on page 281 of course text). • Not an IETF standard • More details at http://www.certicom.com/resources/ecc_chall/challenge.html • Prone to Attacks • chosen plaintext data recovery attack • datagram truncation attack • message forgery attack, and • key-search shortcut for some exportable keys. • For more details visit http://www.cc.jyu.fi/~mjos/wtls.pdf • WAP 2.0 adopts TLS protocol. "CSC8530 Distributed Systems", Summer 2002

  18. WDP vs. UDP • WDP is almost equivalent to UDP • Purpose: • To enable applications to operate transparently over different available bearer services • Why WDP and not UDP ? • To accommodate airlink addresses ("MSISDN number [handset serial number], IP address, X.25 address or other identifier") • To overcome airlink restrictions on packet size and even character sets. "CSC8530 Distributed Systems", Summer 2002

  19. WDP vs. UDP (contd.) "CSC8530 Distributed Systems", Summer 2002

  20. WDP vs. UDP (contd.) • Services offered by WDP : • Application addressing by port numbers • Segmentation and Re-assembly (optional) • Error Detection (optional) "CSC8530 Distributed Systems", Summer 2002

  21. WCMP vs. ICMP • Obsolete • Included in WAP 1.0 • Removed in WAP 1.1 "CSC8530 Distributed Systems", Summer 2002

  22. Competing Technologies • 3G • If a mobile can tx/rx data at ~2Mbps, what is the use of WAP Gateway in between ? • WAP is trying to survive with its WAP Push technology for location based services. • Mobile IP and Wireless LAN (802.11b) • Lightweight & Efficient Application Protocols (LEAP) • IETF standards, an alternative to WAP • Rejected by big players like Nokia, Motorola etc. Seems to be no development is going on in this front. "CSC8530 Distributed Systems", Summer 2002

  23. References • Attacks on WTLS: http://www.cc.jyu.fi/~mjos/wtls.pdf • Converting HTML to WML: http://www.vbxml.com/wap/articles/htmlwml/default.asp • WAP God: http://www.wapforum.com • Criticism: http://www.4k-associates.com/4K-Associates/IEEE-L7-WAP-BIG.html • Possible Future: http://www.nokia.com/wap/wap.html • Brief Tutorial: http://www.w3schools.com/wap/ • Criticism: http://www.freeprotocols.org/wapTrap/one/ • Tutorial on WML: http://www.iec.org/online/tutorials/wap/index.html "CSC8530 Distributed Systems", Summer 2002

  24. Summary • State what has been learned • WAP Applications • WAP for Distributed Environment • WAP internals in brief • WAP evolution and changes over time • Future prospects/demise ?! • Request feedback of training session "CSC8530 Distributed Systems", Summer 2002

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