TCP refers to Transmission Control Protocol. It is a connection-oriented, reliable and byte stream-based transport layer communication protocol. In contact with TCP, there is also UDP, which is also an important transmission protocol. TCP provides timeout retransmission, discarding duplicate data, data verification, flow control and other functions to ensure that data can be transmitted from one end to the other
1. Provide reliable transmission of data in an IP environment (one computer sends The byte stream will be sent to other computers on the network without errors, and when computer A receives the data packet, it will also send the data packet back to computer B, which will also generate some traffic), effective flow control, full duplex Operation (data can be transmitted in two directions simultaneously), multiplexing service, is connection-oriented, end-to-end transmission;
2. Connection-oriented: A connection must be established with the other party before formal communication. Create a connected channel for the data to be sent in advance, and then send the data, just like making a phone call.
3. Application protocols supported by TCP: FTP file transfer, RLogin remote login, SMTP POP3 email, NFS network file system, remote printing, remote execution, name server terminal server and other service types.