TAILIEUCHUNG - Lecture Data communications and networks: Chapter 27 - Forouzan

The World Wide Web (WWW) is a repository of information linked together from points all over the world. The WWW has a unique combination of flexibility, portability, and user-friendly features that distinguish it from other services provided by the Internet. Chapter 27 discuss the ideas and issues in the famous world wide web (WWW). It also briefly describes the client/server application program (HTTP) that is commonly used to access the web. | Chapter 27 WWW and HTTP Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 27. 27-1 ARCHITECTURE The WWW today is a distributed client/server service, in which a client using a browser can access a service using a server. However, the service provided is distributed over many locations called sites. Client (Browser) Server Uniform Resource Locator Cookies Topics discussed in this section: 27. Figure Architecture of WWW 27. Figure Browser 27. Figure URL 27. 27-2 WEB DOCUMENTS The documents in the WWW can be grouped into three broad categories: static, dynamic, and active. The category is based on the time at which the contents of the document are determined. Static Documents Dynamic Documents Active Documents Topics discussed in this section: 27. Figure Static document 27. Figure Boldface tags 27. Figure Effect of boldface tags 27. Figure Beginning and ending tags 27. Figure Dynamic document using CGI 27. Figure Dynamic document using server-site script 27. Dynamic documents are sometimes referred to as server-site dynamic documents. Note 27. Figure Active document using Java applet 27. Figure Active document using client-site script 27. Active documents are sometimes referred to as client-site dynamic documents. Note 27. 27-3 HTTP The Hypertext Transfer Protocol (HTTP) is a protocol used mainly to access data on the World Wide Web. HTTP functions as a combination of FTP and SMTP. HTTP Transaction Persistent Versus Nonpersistent Connection Topics discussed in this section: 27. HTTP uses the services of TCP on well-known port 80. Note 27. Figure HTTP transaction 27. Figure Request and response messages 27. Figure Request and status lines 27. Table Methods 27. Table Status codes 27. Table Status codes (continued) 27. Figure Header format

• Quản trị mạng
• Data communications
• Lecture Data communications
• Physical layer
• Data link layer
• Web documents
• Hypertext Transfer Protocol
• Business data communications
• Network criteria
• Data communications system
• Data communications networks
• Media access control
• Network models
• Network standards
• Application layer
• Application architectures
• Digital transmission
• Network and transport layers
• Transport layers
• Local area networks
• Traditional ethernet
• Wireless local area networks
• Wireless LANs
• Backbone networks
• Backbone network architectures
• Circuit switched networks
• Wide area networks
• Network security
• Risk assessment
• Network design
• Traditional network design
• Network management
• Configuration management