《计算机网络和 与因特网》课件第二章客户-服务器交互.ppt

works and s
《计算机网络与因特网》课件
林坤辉
PART work Applications
Chapter 3 Client-Server Interaction
客户-服务器交互
Introduction
works can be interconnected.
Protocol software used to achieve reliable transport across the resulting .
bination working hardware and protocol software results in a general-munication infrastructure.
It allows application programs on an arbitrary pair puters municate.
Every application program must include all tasks assigned to the session, presentation, and application layers of the OSI model.
Comparison between OSI and TCP/IP
Applications supply the high-level services that users access,
And determine how users perceive the capabilities of the underlying .
Application determine the format in which information is displayed and the mechanisms users have to select or access information.
The Functionality Application Software Provides
When an ing message matches exactly what the application has specified, protocol software passes the message to the application.
One application must actively initiate interaction,
while the other application passively waits.
The Client-Server Paradigm客户-服务器模式
The terms client and server refer to the two applications involved in munication.
The application that actively initiates contact is called a client,
While the application that passively waits for contact is called a server.
The client-server relationship is many-to-one. Many clients can use the services of one server.