- Host A sends SYN (synchronization) to Host B
- ISN = 521 so sequence number 521
- Host B returns a SYN acknowledgment (SYN ACK)
- Host B’s ISN is 2000, so sequence number is 2000
- Previous sequence number was 521, so ack no. is 522 (increment)
- Host A sends an ACK to acknowledge the SYN ACK
- Host B’s ISN was 2000, so ack no. is 2001
Each host tells its ISN to the other host
