TCP Connection Lifecycle
Network Fundamentals
Overview
TCP creates state through SYN, SYN-ACK and ACK. Sequence numbers track byte streams; acknowledgements report the next expected byte. Retransmission handles loss, and flow control protects the receiver. FIN closes a direction gracefully; RST aborts state.
Protocol stages
- 1SYN
- 2SYN-ACK
- 3ACK
- 4Data / acknowledgement
- 5FIN / ACK
Interactive exercise
Knowledge check
Client sends SYN with sequence 100. What acknowledgement should the server SYN-ACK contain?
Educational model — not real hardware, traffic or official certification.