Page 33 Figure 9 Recovery from old Duplicate SYN TCP A TCP B SEQNA Page33 Figure 9 1 CLOSED LISTEN SEQNA SEQ300 ShouldACK NA ShouldACK ID: 271758
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Slide1
Recovery from old duplicate SYHPage 33, Figure 9Slide2
Recovery from old Duplicate SYN
TCP A
TCP B
SEQ=NA
Page:33
Figure. 9
1. CLOSED LISTEN
SEQ=NA
SEQ=300
Should_ACK
=NA
Should_ACK
=NA
SEQ=90
CTL=SYN
ACK= DATA=Slide3
Recovery from old Duplicate SYN
TCP A
TCP B
SEQ=NA
SEQ=300
Page:33
Figure. 9
SEQ=100
SEQ=100
CTL=SYN
ACK= DATA=
Should_ACK
=NA
Should_ACK
=NA
SEQ=90
CTL=SYN
ACK= DATA=
1. CLOSED LISTEN
2. SYN-SENT --> <SEQ=100><CTL=SYN> ...Slide4
Recovery from old Duplicate SYN
TCP A
TCP B
SEQ=300
Page:33
Figure. 9
Should_ACK
=NA
Should_ACK
=NA
SEQ=90
CTL=SYN
ACK= DATA=
2. SYN-SENT --> <SEQ=100><CTL=SYN> ...
3. (duplicate) ... <SEQ=90><CTL=SYN> --> SYN-RECEIVED
SEQ=100
Should_ACK
=91
SEQ=100
CTL=SYN
ACK= DATA=Slide5
Recovery from old Duplicate SYN
TCP A
TCP B
SEQ=300
Page:33
Figure. 9
Should_ACK
=NA
3. (duplicate) ... <SEQ=90><CTL=SYN> --> SYN-RECEIVED
4. SYN-SENT <-- <SEQ=300><ACK=91><CTL=SYN,ACK> <-- SYN-RECEIVED
SEQ=100
Should_ACK
=91
SEQ=90
CTL=SYN
ACK= DATA=
SEQ=300
CTL=SYN
ACK=91
DATA=
?
SEQ=100
CTL=SYN
ACK= DATA=Slide6
Recovery from old Duplicate SYN
TCP A
TCP B
SEQ=300
Page:33
Figure. 9
Should_ACK
=NA
4. SYN-SENT <-- <SEQ=300><ACK=91><CTL=SYN,ACK> <-- SYN-RECEIVED
5. SYN-SENT --> <SEQ=91><CTL=RST> --> LISTEN
SEQ=100
Should_ACK
=91
?
SEQ=100
CTL=SYN
ACK= DATA=
SEQ=91
CTL=RST
ACK= DATA=
Should_ACK
=NA
SEQ=400
SEQ=300
CTL=SYN
ACK=91
DATA=Slide7
Recovery from old Duplicate SYN
TCP A
TCP B
Page:33
Figure. 9
Should_ACK
=NA
5. SYN-SENT --> <SEQ=91><CTL=RST> --> LISTEN
6. ... <SEQ=100><CTL=SYN> --> SYN-RECEIVED
SEQ=100
SEQ=100
CTL=SYN
ACK
=
DATA=
Should_ACK
=NA
SEQ=400
Should_ACK
=101Slide8
Recovery from old Duplicate SYN
TCP A
TCP B
Page:33
Figure. 9
Should_ACK
=NA
6. ... <SEQ=100><CTL=SYN> --> SYN-RECEIVED
7. SYN-SENT <-- <SEQ=400><ACK=101><CTL=SYN,ACK> <-- SYN-RECEIVED
SEQ=100
SEQ=400
SEQ=400
CTL=SYN
ACK=101
DATA=
Should_ACK
=101
Should_ACK
=401
SEQ=101
SEQ=100
CTL=SYN
ACK= DATA=Slide9
Recovery from old Duplicate SYN
TCP A
TCP B
Page:33
Figure. 9
Should_ACK
=401
7. SYN-SENT <-- <SEQ=400><ACK=101><CTL=SYN,ACK> <-- SYN-RECEIVED
8. ESTABLISHED --> <SEQ=101><ACK=401><CTL=ACK> --> ESTABLISHED
SEQ=101
SEQ=400
Should_ACK
=101
SEQ=400
CTL=SYN
ACK=101
DATA=
SEQ=101
CTL=
ACK=401
DATA=
Should_ACK
=101
SEQ=401