1. RFC 793 State machine study

2. Normal close sequence Page 39, Figure 13

3. 1. ESTABLISHED ESTABLISHED
Normal close sequence
Page:39
Figure. 13
TCP A
TCP B
SEQ=100
Should_ACK=300
SEQ=300
Should_ACK=100
1. ESTABLISHED ESTABLISHED

4. Normal close sequence TCP A TCP B 2. (Close) 0
Page:39
Figure. 13
TCP A
TCP B
SEQ=100
Should_ACK=300
SEQ=300
SEQ=300
Should_ACK=101
Should_ACK=100
SEQ=100 CTL=FIN
ACK=300 DATA=
2. (Close)
FIN-WAIT-1 --> <SEQ=100><ACK=300><CTL=FIN,ACK> --> CLOSE-WAIT

5. Normal close sequence TCP A TCP B
Page:39
Figure. 13
TCP A
TCP B
SEQ=100
SEQ=101
Should_ACK=300
Should_ACK=300
SEQ=300
Should_ACK=101
SEQ=300 CTL=
ACK=101 DATA=
3. FIN-WAIT-2 <-- <SEQ=300><ACK=101><CTL=ACK> <-- CLOSE-WAIT

6. Normal close sequence TCP A TCP B 4. (Close)
Page:39
Figure. 13
TCP A
TCP B
SEQ=101
SEQ=101
Should_ACK=301
Should_ACK=300
SEQ=300
Should_ACK=101
SEQ=300 CTL=FIN
ACK=101 DATA=
(Close)
TIME-WAIT <-- <SEQ=300><ACK=101><CTL=FIN,ACK> <-- LAST-ACK

7. Normal close sequence TCP A TCP B
Page:39
Figure. 13
TCP A
TCP B
SEQ=101
Should_ACK=301
SEQ=NA
SEQ=300
SEQ=301
Should_ACK=101
Should_ACK=101
Should_ACK=NA
SEQ=101 CTL=
ACK=301 DATA=
5. TIME-WAIT --> <SEQ=101><ACK=301><CTL=ACK> > CLOSED

8. Normal close sequence TCP A TCP B 6. (2 MSL) CLOSED Page:39 Figure. 13
SEQ=NA
SEQ=101
Should_ACK=301
Should_ACK=NA
SEQ=NA
Should_ACK=NA
6. (2 MSL)
CLOSED