1. RFC 793 State machine study

2. Simultaneously active SYN Page 32, Figure 8

3. Simultaneously active SYN Page:32 Figure. 8 1. CLOSED CLOSED TCP A TCP B SEQ=NA Should_ACK=NA

4. Simultaneously active SYN TCP A TCP B Page:32 Figure. 8 1. CLOSED CLOSED 2. SYN-SENT -->... SEQ=100 CTL=SYN ACK= DATA= SEQ=NA SEQ=100 Should_ACK=NA SEQ=NA Should_ACK=NA

5. Simultaneously active SYN TCP A TCP B Page:32 Figure. 8 2. SYN-SENT -->... 3. SYN-RECEIVED <-- SYN-SENT SEQ=100 CTL=SYN ACK= DATA= Should_ACK=NA SEQ=NA Should_ACK=NA SEQ=100 SEQ=300 SEQ=300 CTL=SYN ACK= DATA= Should_ACK=301

6. Simultaneously active SYN TCP A TCP B Page:32 Figure. 8 3. SYN-RECEIVED <-- SYN-SENT 5. SYN-RECEIVED -->... SEQ=100 CTL=SYN ACK= DATA= Should_ACK=NA SEQ=100 SEQ=300 CTL=SYN ACK= DATA= Should_ACK=301 SEQ=100 CTL=SYN ACK=301 DATA= SEQ=300

7. Simultaneously active SYN TCP A TCP B Page:32 Figure. 8 5. SYN-RECEIVED -->... 4.... --> SYN-RECEIVED SEQ=100 CTL=SYN ACK= DATA= Should_ACK=NA SEQ=100 Should_ACK=301 SEQ=100 CTL=SYN ACK=301 DATA= SEQ=300 Should_ACK=101

8. Simultaneously active SYN TCP A TCP B Page:32 Figure. 8 4.... --> SYN-RECEIVED 6. ESTABLISHED <-- SYN-RECEIVED SEQ=100 CTL=SYN ACK=301 DATA= SEQ=100 Should_ACK=301 SEQ=100 CTL=SYN ACK= DATA= SEQ=300 SEQ=300 CTL=SYN ACK=101 DATA= Should_ACK=101 SEQ=101 Should_ACK=301

9. Simultaneously active SYN TCP A TCP B Page:32 Figure. 8 6. ESTABLISHED <-- SYN-RECEIVED 7.... --> ESTABLISHED SEQ=101 Should_ACK=301 SEQ=300 Should_ACK=101 SEQ=101 CTL= ACK=301 DATA= Should_ACK=101 SEQ=301