Ports can be divided into virtual ports and physical ports, where virtual ports refer to the ports inside the computer or in the switch router and are invisible. Such as port 80, port 2 1, port 23, etc. Physical ports, also known as interfaces, are visible ports, RJ45 network ports on the computer backplane and RJ45 ports, such as switch router hubs. Phones using RJ 1 1 jack also belong to the category of physical ports.
Port classification:
1, TCP port
Transmission control protocol transmission control protocol. TCP is a connection-oriented, reliable and byte-stream-based transport layer communication protocol, which is regulated by RFC 793 of IETF. In the simplified OSI model of computer network, it completes the functions specified by the fourth layer transport layer, and UDP is another important transport protocol at the same layer.
2.UDP port
User datagram protocol. UDP is a connectionless transport layer protocol in OSI reference model, which provides simple and unreliable information transmission service oriented to transactions. UDP protocol is basically the interface between IP protocol and upper layer protocol. UDP protocol is suitable for multiple applications running on the same device.