Wireless Application Protocol (WAP) Network Computing Lab 김형민 (meruru98@nate.com)

Why Choose WAP Wireless handheld devices Restricted user interface (small displays and keypads) Less powerful CPU Reduced memory capacity Wireless Network Limited bandwidth Longer latency Lower degree of reliability Network Computing Lab

The WAP Model Network Computing Lab

The WAP Model Network Computing Lab

WAP Gateway The WAP Gateway utilizes Web proxy technology to provide efficient wireless access to the Internet Implementation of WAP protocol stack layers Access Control Protocol conversion: WSP <-> HTTP Domain Name resolution HTML to WML conversion Encording of WML content WMLScript compilation Security Provide caching for frequently accessed content Network Computing Lab

WAP Protocol Stack Network Computing Lab

WAP Protocols WDP (Wireless Datagram Protocol) End-To-End 전송을 위해 port 어드레싱을 제공 인터넷의 UDP와 같은 전송 기능을 담당 WTLS (Wireless Transport Layer Security) 인터넷의 TLS (Transport Layer Security)를 근간으로 작성된 보안 프로토콜 인증(Authentication), 부인봉쇄(Non-Repudiation), 무결성(Constraint), 기밀성(Security) 등의 보안 서비스를 제공 WTP (Wireless Transaction Protocol) 트랜잭션 형태의 데이터 전송 기능을 제공 신뢰성 및 비신뢰성 전송 기능을 제공하고 오류복구를 위해 재전송 기능도 담당 Network Computing Lab

WAP Protocols WSP (Wireless Session Protocol) HTTP/1.1에 상응하는 기능을 정의 장시간 활용의 세션을 정의하고, 세션 관리를 위해 suspend/resume 기능도 제공 프로토콜 기능에 대한 협상도 가능하게 함 WAE(Wireless Application Environment) 일반적, 다목적 응용을 개발하기 위한 응용 환경에 대한 규격을 정의 WML(Wireless Markup Language), WMLScript 등을 정의하여 휴대 단말기에 적용될 수 있는 소규모 브라우저를 개발할 수 있도록 함 Network Computing Lab

WAP 1.2 & 2.0 Network Computing Lab

WAP UAProf and Caching WAP proxy may provide a variety of functions Protocol Gateway The protocol gateway translates requests from a wireless protocol stack to the WWW protocols The gateway also performs DNS lookups of the servers named by the client in the request URLs Content Encoders and Decoders The content encoders can be used to translate WAP content into a compact format that allows for better utilisation of the underlying link due to its reduced size User Agent Profile Management User agent profiles describing client capabilities and personal preferences [UAProf] are composed and presented to the applications Caching Proxy A caching proxy can improve perceived performance and network utilisation by maintaining a cache of frequently accessed resources Network Computing Lab

Wireless Bearers for WAP The WAP protocol stack is built on top of wireless bearer services IP-based bearer GPRS UDP Non-IP-based bearer GSM SMS GSM USSD ReFlex IS-637SMS Network Computing Lab

WAP SDK Simulator Network Computing Lab

Mobile Station Application Execution Environment 단말기 응용 프로그램 실행환경 서비스 능력을 협상하여 MS에서 표준화된 실행환경을 제공 MExE classmark 1 WAP environment MExE classmark 2 Personal Java environment Future classmark Java-packages APIs 음성인식 On-line (de)compression을 가진 video-I/O 초고속 로컬 통신 Network Computing Lab