Mid twentieth century , All aspects of social science and technology development , Network also came into being . stay 20 The end of the century 10 Mid year , People were surprised to find , Telephone , Television and computers are converging rapidly ; Access to information , storage , With the development of computer transmission and processing, the phenomenon of islands gradually disappears . Computer network is the product of the close combination of computer technology and communication technology , It is the infrastructure of modern information society . It provides people with information exchange , resource sharing , Instant messaging and other means ,
Changed people's ideas , Working mode and lifestyle , Changed the way the whole world works .
The birth of the first generation computer network —— Terminal oriented computer network
Second generation computer network —— packet switching
Third generation computer network —— Standardization network
Fourth generation computer network —— Network interconnection
Definition of computer network ：
Computers distributed in different geographical locations , terminal , Connected by communication equipment and lines , With fully functional network software , System for realizing mutual communication and network resource sharing .
Main functions of computer network ：
1. data communication
2. resource sharing
3. Increase sharing
4. Improve system processing function
Composition of computer network :
Computer network is a very complex system , It consists of network transmission media and equipment responsible for transmitting data , Computer terminal equipment and server using network , And network operating system .
1. Network transmission medium ： Twisted pair cable , Optical fiber , microwave , Coaxial cable
2. Network switching equipment ： Connect computers together , And forward the computer's packets . therefore , computer
To connect to a LAN , You must first connect to the switch .
3. Network switching equipment ： Router
4. Network terminal and server
5. Network operating system
Classification of computer networks ：
LAN , Metropolitan area network , Wide area network
Topology of computer network ：
Physical topology and logical topology
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