Question

• Simultaneous TCP connection initiations are rare, but simultaneous connection termination is relatively common. How do two TCP nodes negotiate the simultaneous sending of FIN packets to one another? Draw the ladder diagram, and label the states on each side. Which node goes into TIMEWAIT state?

Answer 1

Actually, when connection termination is required in TCP a FIN packet is sent. Normally,

the user will send a FIN and wait till its own FIN is acknowledged and then deletes the

connection.

So far, a connection termination make use of four-way handshake protocol. When a node

wishes to stop its half of the connection, it transmits a FIN packet while the other node

acknowledges with an ACK. Certainly, simultaneous connection termination is possible,

when both the TCP nodes transmit FIN packet simultaneously.

Connection termination requires a pair of FIN and ACK segments from each TCP

endpoint. When the section that sent the initial FIN has responded with the final ACK, it

waits for a timeout before closing the connection, during which the local ports are

unavailable for new connections.

Initiator node was the first one to send the first FIN, before the receiver node, thereby

making the initiator node to go into TIMEWAIT state.