The communications techniques covered so far have been concerned with centralised systems. Terminal networks are all built around a central computer; similarly remote job entry stations are usually connected to a single computer. In the remaining chapters some of the problems and techniques of a network of intercommunicating devices are discussed. The devices at present connected to networks are usually general purpose computers, with their own terminal networks. One reason for networking multi-access computers, rather than terminals or smaller devices, is that these computer systems already existed when networking was proposed. A second reason is that the protocols used in computer networks are very complex so that only a large computer system would have sufficient spare computing power to implement them. However terminals can be directly attached to a network, as will be shown in chapter 9.
KeywordsLocal Network Wide Area Network Packet Switching Circuit Switching Destination Address
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