The production of computer communication networks
With the advent of computers, transceivers can transmit data over telephone lines to distant computers. Since then, the user can type in their own on the teletype machine remote program, the result of the computer to calculate and can transmit to far from a computer on the teletype machine and printed, it marks the combination of computer and communication. First computer and remote terminal connection, is an online system, and add the line in the computer controller, computer and terminal through a modem can be connected to a telephone line, complete the conversion of analog and digital signals. Later, multiple circuit controllers emerged, which could be connected to multiple remote terminals and computers via telephone lines, the first generation of computer networks. Later, with the front-end processor, the whole communication business was completed, and the computer was specially designed for data processing, which improved the efficiency of the mainframe (computer). In order to save communication lines and reduce communication costs, a concentrator can be added to the area where the remote terminal is more dense.
The composition of the folded computer communication network
With the development of data communication network, computer communication network has gradually developed into a network centric. The typical computer communication network is divided into user subnet and communication subnet structure from the logical function, as shown in figure 7. Figure 7. R network structure FIG. 7 structure of r network A user subnet is a collection of all end points (including all of their equipment) and links that connect these nodes, with a host, terminal controller, terminal, etc. A communication subnet is a link aggregation of nodes connected to each node. The specific equipment has node processor, transmission link and communication software.