Question: What is the usage of TCP (Transmission Control Protocol)?

TCP (Transmission Control Protocol) is the popular Transport layer protocol that used in TCP/IP networking.

This is a connection oriented protocol that normally used in client/server networking environment with a requirement to establish the connection first before sending/receiving the data. It’s like making a phone call, the call connection is established when somebody pick up the phone, then we can only start to talk/listen. We also won’t simply lose the connection after that until we hang up the phone.

By using TCP, every packet will be tagged with sequence number to track the packets and the acknowledgement will be received if the packets are received successfully. Packet resending will be done after some time if no acknowledgement received. This process will ensure the connection reliability and avoid packet loss.

Majority of the applications, such as web application, telnet, ssh, ftp and smtp are built with TCP.