How TCP establish and close connection?

TCP establish connection #

TCP close connection #

Why TCP has TIME_WAIT? #

Client normally waits for 2 maximum segment lifetime (MSL) and close the connection. There are two main reason:

• Ensure all old packets is disapper on the internet.
• ACK from client might lose due to the network. Therefore, server will resend FIN after timeout. If client closes the connection immediately, client can’t receive the new FIN.