History of the development of computer networks
Computer network from the 1950s to the last century and now has seventy years of development history, in the long course of decades, we experienced a total of four stages of development.
- A computer network for the terminal
- Multiple computers interconnected computer networks
- Computer network for Standardization
- Global computer network interconnection
A computer network for the terminal
A terminal for a computer network host is connected to multiple terminals, all the information and communication program runs are processed by the central host; with the increase of the terminal, in order to reduce the pressure of the central host, a communication processor increases, it responsible for the control and communication between the terminal; a terminal in a more cluster sets multiplexer or concentrator, multiplexer and concentrated by low-speed line is connected with the terminal, and communicate with the high-speed line the processor is connected.
Multiple computers interconnected computer networks
In 1965, the successful implementation of the first packet switching network ARPANet, which is the predecessor of the Internet
Standards for computer network
Release OSI-RM reference model (Open Systems Interconnection Basic Reference Model)
It introduced the TCP / IP protocol famous, and to establish it as the core of the Internet
Classification of computer networks
According to the topology of points
According topology can be divided into a star topology, tree topology, ring topology, bus topology, mesh topology
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Star topology: the middle is a hub, a plurality of ports, each workstation to a network cable connected to the hub
- Tree topology: a root node and multi-branch, in addition to the leaf node, the other branch nodes are forwarding node
- Bus topology: of all the hosts connected to the interface via a single transmission line is called a bus, a master sends each message must be transmitted on the host, the host information can be accepted by other
- Ring topology: all hosts are connected end to end through the communication line, information is transmitted in one direction in the loop between hosts
- Mesh topology: an irregular connections from one point to another may be multiple lines, so one line when a fault, the line information may be transmitted from other
Coverage according points
According to coverage points can be divided into personal area networks, local area networks, metropolitan area networks, wide area networks
- Personal area network: a personal area is in use the personal electronic device connected using a wireless network, generally within 10m
- Local Area Network: LAN, typically within a few hundred meters to several kilometers, the transmission speed
- MAN: 10km to 200km, a metropolitan area covering a plurality of local area networks, this part is responsible for the communication between the local area network
- 广域网:几百公里到几千公里.广域网一般是把不同城市之间的局域网城域网互连,使不同局域网之间可以彼此通信