TAILIEUCHUNG - Lecture Business data communications: Chapter 2 - Behrouz A. Forouzan

Chapter 2 - Application layer. his chapter explores the different application programs, or services, available at the topmost layer, layer five, of the Internet model. In this chapter, we introduce the application layer and its relationships to the other layers. We discuss the client-server paradigm, the only one used today in the Internet. We also discuss addressing, a feature inseparable from the application layer. We then explore the most common application programs used in the Internet including electronic mail, file transfer, remote logging, World Wide Web, list servers, videoconferencing, and chatting. | Chapter 2 Application Layer The client-server paradigm. Electronic mail. File transfer. Remote login. After reading this chapter, the reader should be able to understand: OBJECTIVES The World Wide Web. Other applications such as videoconferencing and chatting. INTRODUCTION Figure 2-1 Position of the application layer in the Internet model CLIENT-SERVER PARADIGM Application-layer programs in the Internet model communicate using the client-server paradigm. Note: Figure 2-2 Client-server model Figure 2-3 Client-server relationship In the client-server paradigm, many clients can be served by one server, either one at a time or concurrently. Note: In the client-server paradigm, a client runs for a specific period of time; the server runs continuously. Note: In the client-server paradigm, there are specific servers and normally one general-purpose server. Note: ADDRESSING Technical Focus: Domain Name System (DNS) The following are traditional and new domain names: Traditional:

• Quản trị mạng
• Business data communications
• Data communications
• Business data communications
• Application layer
• Electronic mail
• File transfer
• Data link layer
• Network criteria
• Data communications system
• Data communications networks
• Media access control
• Network models
• Network standards
• Application layer
• Application architectures
• Physical layer
• 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