The communication between computers is essentially the communication of processes between different computers. The port number is the only number that represents these processes. (Process: running program) The port number has 16 digits, from 0 to 65535, and a * * * has two 16 port numbers.

You can find the application running on the computer by the port number. For example, the corresponding port number of the Web server is 80, and the function of surfing the Internet is realized through port 80. The port address works at the transport layer and will not change during transmission. The port address is the port number.

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Computer network connects multiple computers with independent functions and their external devices located in different geographical locations through communication lines. A computer system that realizes resource sharing and information transmission under the management and coordination of network operating system, network management software and network communication protocol.

The development of computer network has gone through three stages: terminal-oriented single-stage computer network, computer-to-computer network and open standardized computer network. ?

Generally speaking, a computer network is formed by physically (or logically) connecting multiple computers (or other computer network devices) through transmission media and software.

Generally speaking, the composition of computer network basically includes four parts: computer, network operating system, transmission medium (tangible or intangible, such as invisible electromagnetic waves in wireless network) and corresponding application software.

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