无线网路技术的应用.ppt

1、2020/10/1,1,校園無線網路技術與應用發展,Sheng-Tzong Cheng 鄭憲宗 .tw .tw 06-2757575 ext. 62529,2020/10/1,成大資訊 鄭憲宗,2,Outline,無線區域網路 IEEE 802.11 無線應用通訊協定 WAP,2020/10/1,成大資訊 鄭憲宗,3,無線區域網路通訊協定 Wireless Local Area Network (IEEE 802.11),2020/10/1,成大資訊 鄭憲宗,4,無線區域網路標準-IEEE 802.11,S

2、pecifies a single Medium Access Control (MAC) sublayer and 3 Physical Layer Specifications. Stations can operate in two configurations : Ad-hoc mode Infrastructure mode Three PHY specifications Frequency Hopping Spread Spectrum (FHSS). Direct Sequence Spread Spectrum (DSSS). Infrared PHY.,2020/10/1,

3、成大資訊 鄭憲宗,5,IEEE 802.11規範,IEEE Project 802 Charter: Local 40% : 60% (2005),2020/10/1,成大資訊 鄭憲宗,35,全球無線通訊用戶成長,2020/10/1,成大資訊 鄭憲宗,36,預估未來WAP手機的佔有率,2020/10/1,成大資訊 鄭憲宗,37,2020/10/1,成大資訊 鄭憲宗,38,2020/10/1,成大資訊 鄭憲宗,39,手持型元件之延革,2020/10/1,成大資訊 鄭憲宗,40,2020/10/1,成大資訊 鄭憲宗,41,bring the internet content and advance

4、d services to 後PC 時代之users create a global wireless protocol to work across differing wireless network technologies enable applications to scale across a variety of transport options and device types,Whats WAP for?,2020/10/1,成大資訊 鄭憲宗,42,What is defined in WAP?,Micro-Browser Scripting to enhance MS c

5、apabilities WTA/WTAI for telephone functionality (e.g. call chains) Content Formats business card (vCard ) calendar event (vCalendar ) Layered Telecommunication Stack,2020/10/1,成大資訊 鄭憲宗,43,Comparison,2020/10/1,成大資訊 鄭憲宗,44,2020/10/1,成大資訊 鄭憲宗,45,Goals for WTP (WAP v1.1),a common interface to physical

6、transport mechanisms provide a port- based abstract interface to upper layer protocols allow applications designed independent from specific transports extensible to a variety of digital wireless networks and future transport options,2020/10/1,成大資訊 鄭憲宗,46,Goals for WTP (cont.),supports connection- o

7、riented, transaction, and datagram modes optimize for narrow to medium bandwidth channels to be capable of implementation in a low memory footprint, suitable for standard or low- IQ handsets,2020/10/1,成大資訊 鄭憲宗,47,Requirements for WTP,WTP/ C provides a reliable connection- oriented service to the upp

8、er layer WTP/ T provides a reliable transaction- oriented service suitable for web browsing WTP/ D provides a datagram service lightweight : implementable in = 10Kb (low memory / computational needs),2020/10/1,成大資訊 鄭憲宗,48,WTP/D features (WDP in WAP v 1.2),WTP/ D (Datagram) provides a connection- les

9、s, unreliable datagram service WTP/ D is replaced by UDP when used over an IP network layer. uses the Service Primitive T- UnitData. req .ind,2020/10/1,成大資訊 鄭憲宗,49,WAP v 1.2,2020/10/1,成大資訊 鄭憲宗,50,WTP/T features (WTP in WAP v 1.2),WTP/ T (Transaction) provides reliable data transfer based on request/

10、 reply paradigm no explicit connection setup or tear down data carried in first packet of protocol exchange seeks to reduce 3- way handshake on initial request,2020/10/1,成大資訊 鄭憲宗,51,WTP/T features (cont.),supports retransmission of lost packets selective- retransmission segmentation / re- assembly p

11、ort number addressing (specific to WTP/ T) flow control message oriented (not stream) supports an Abort function for outstanding requests,2020/10/1,成大資訊 鄭憲宗,52,Wireless Session Protocol,WSP/ B provides upper layers with session services and management WSP/ B Provides semantics and mechanisms based o

12、n HTTP 1.1 WSP provides means to : establish a reliable session from client to server agree on common level of protocol functionality by capability negotiation compact encoding suspend and resume,2020/10/1,成大資訊 鄭憲宗,53,WSP features,HTTP 1.1 functionality Exchange of client and server session headers

13、Interrupt mechanism for transactions in process Content Push from server to client Negotiation for multiple, simultaneous asynchronous transactions,2020/10/1,成大資訊 鄭憲宗,54,WTLS Record Protocol,4 record protocol clients: The handshake protocol The change cipher spec protocol The alert protocol The appl

14、ication data protocol WTLS connection state : the operating environment for record protocol compression/ encryption algorithm MAC algorithm - keys,2020/10/1,成大資訊 鄭憲宗,55,Record Protocol Usage,Handshake protocol Negotiate secure attributes of a secure session authentication, security parameter setting

15、s Change cipher spec protocol Signal transitions in ciphering strategies sent before verifying finished message Alert protocol convey the severity of the message and a description of the alert,2020/10/1,成大資訊 鄭憲宗,56,Wireless Application Environment (WAE),An Internet (WWW) programming model Vendor- co

16、ntrolled MMI Initial focus on phones Slow bearers Small memory Limited CPU Small screen Limited input model,2020/10/1,成大資訊 鄭憲宗,57,WAE Components,Architecture Application model Browser, Gateway, Content Server WML (Wireless Markup Language) Display language WMLScript Scripting language Content Format

17、s Data exchange,2020/10/1,成大資訊 鄭憲宗,58,WAE In- Device Architecture,2020/10/1,成大資訊 鄭憲宗,59,WML,Tag- based browsing language: Screen management (text, images) Data input (text, selection lists, etc.) Hyperlinks & navigation support Syntax: W3C XML (SGML derivative) Inherits technology from HDML and HTML

18、,2020/10/1,成大資訊 鄭憲宗,60,WML (cont.),Card metaphor User interactions are split into cards Navigation occurs between cards State management and variables Reduce network traffic Results in better caching Explicit inter- card navigation model Hyperlinks UI Event handling History,2020/10/1,成大資訊 鄭憲宗,61,WML

19、 Example, Welcome! Enter name: speed: Fast Slow ,2020/10/1,成大資訊 鄭憲宗,62,WMLScript,Scripting language: Procedural logic, loops, conditionals, etc. Optimized for small- memory, small- cpu devices Derived from JavaScript Integrated with WML Powerful extension mechanism Reduces overall network traffic,20

20、20/10/1,成大資訊 鄭憲宗,63,WMLScript (cont.),Bytecode-based virtual machine Stack-oriented design ROM-able Designed for simple, low-impact implementation Compiler in network Better network bandwidth use Better use of terminal memory/ cpu,2020/10/1,成大資訊 鄭憲宗,64,2020/10/1,成大資訊 鄭憲宗,65,2020/10/1,成大資訊 鄭憲宗,66,2020/10/1,成大資訊 鄭憲宗,67,WAP Gateway,2020/10/1,成大資訊 鄭憲宗,68,WAP Application Server,2020/10/1,成大資訊 鄭憲宗,69,2020/10/1,成大資訊 鄭憲宗,70,WAP Push Technology,2020/10/1,成大資訊 鄭憲宗,71,WAP怎麼了？,歐洲在兩年內至少應有10億