CN-5-1-2 - Sequence # - Less than or equal to the value in the existing entry
Host
HA----------R2----------R1----------R0
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|---- |---- |----MN |----CN(NUT)
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Home Link Link2 Link1 Link0
(Foreign) (Foreign)
Link0 3ffe:501:ffff:100::/64 Link1 3ffe:501:ffff:101::/64 Foreign Link Link2 3ffe:501:ffff:102::/64 Foreign Link 2 Home Link 3ffe:501:ffff:104::/64 Home Link CN(NUT) 3ffe:501:ffff:100::X
Auto Configuration (InterfaceID)MN(in Link1) 3ffe:501:ffff:101::Y
Increased in each test (InterfaceID)MN care-of address MN(in Home Link) 3ffe:501:ffff:104::Y
Increased in each test (InterfaceID)MN home address R0(Link0) 3ffe:501:ffff:100::1 R1(Link1) 3ffe:501:ffff:101::1 R2(Link2) 3ffe:501:ffff:102::1 HA(Home Link) 3ffe:501:ffff:104::1
Reboot NUT (reboot.rmt)
MN R1 HA R0 CN(NUT)
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| | | |------>| 1.RA
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| | | |------>| 2.NS
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| | | |<------| 3.NA
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|-------------->|-------------->| 4.Echo Request
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|<--------------|<--------------| 5.Echo Reply
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|------------------------------>| 6.Echo Request(Home Address option)
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|<------------------------------| 7.BE(Status=1)
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|------------------------------>| 8.CoTI
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|-------------->|-------------->| 9.HoTI
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|<------------------------------| 10.CoT
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|<--------------|<--------------| 11.HoT
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|------------------------------>| 12.BU(Sequence No=10000)
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|<------------------------------| 13.BA(Status=0 Sequence No=10000)
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|------------------------------>| 14.BU(Sequence No=10000)
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|<------------------------------| 15.BA(Status=135 Sequence No=10000) (*1)
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|------------------------------>| 16.BU(Sequence No=42768)
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|<------------------------------| 17.BA(Status=135, Sequence No=10000) (*2)
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|------------------------------>| 18.BU(Sequence No=65536)
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|<------------------------------| 19.BA(Status=135, Sequence No=10000) (*3)
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1. Send Router Advertisement. 2. Send Neighbor Solicitation. 3. Receive Neighbor Advertisement. 4. Send ICMP Echo Request. 5. Receive ICMP Echo Reply. 6. Send ICMP Echo Request(Home Address option). 7. Receive Binding Error(Status=1). 8. Send Care-of Test Init. 9. Send Home Test Init. 10. Receive Care-of Test. 11. Receive Home Test. 12. Send Binding Update(Sequence No=10000). 13. Receive Binding Acknowledgement(Status=0 Sequence No=10000). 14. Send Binding Update(Sequence No=10000). 15. Receive Binding Acknowledgement(Status=135 Sequence No=10000). 16. Send Binding Update(Sequence No=42768). 17. Receive Binding Acknowledgement(Status=135 Sequence No=10000). 18. Send Binding Update(Sequence No=65536). 19. Receive Binding Acknowledgement(Status=135 Sequence No=10000).
Packet Format 14. Binding Update 15. Binding Acknowledgement 16. Binding Update 17. Binding Acknowledgement 18. Binding Update 19. Binding Acknowledgement
(*1) MN receives Binding Acknowledgement. - The Destination Address is set to the Source Address of the Binding Update (MN care-of address). - The Status field is set to 135. - The Sequence # field is set to the value in the last successful Binding Update. - Binding Authorization Data option is included. - Authenticator field of Binding Authorization Data option has the valid value.
(*2) MN receives Binding Acknowledgement. - The Destination Address is set to the Source Address of the Binding Update (MN care-of address). - The Status field is set to 135. - The Sequence # field is set to the value in the last successful Binding Update. - Binding Authorization Data option is included. - Authenticator field of Binding Authorization Data option has the valid value.
(*3) MN receives Binding Acknowledgement. - The Destination Address is set to the Source Address of the Binding Update (MN care-of address). - The Status field is set to 135. - The Sequence # field is set to the value in the last successful Binding Update. - Binding Authorization Data option is included. - Authenticator field of Binding Authorization Data option has the valid value.
(draft-ietf-mobileip-ipv6-24.txt)
9.5.1 Receiving Binding Updates
Before accepting a Binding Update, the receiving node MUST validate the Binding Update according to the following tests:
(snip)
o The Sequence Number field in the Binding Update is greater than
the Sequence Number received in the previous valid Binding Update
for this home address, if any.
(snip)
This Sequence Number comparison MUST be performed modulo 2**16,
i.e., the number is a free running counter represented modulo
65536. A Sequence Number in a received Binding Update is
considered less than or equal to the last received number if its
value lies in the range of the last received number and the
preceding 32768 values, inclusive. For example, if the last
received sequence number was 15, then messages with sequence
numbers 0 through 15, as well as 32783 through 65535, would be
considered less than or equal.
(snip)
If the Home Registration (H) bit is set, the Nonce Indices mobility option MUST NOT be present.
If the mobile node sends a sequence number which is not greater than the sequence number from the last valid Binding Update for this home address, then the receiving node MUST send back a Binding Acknowledgement with status code 135, and the last accepted sequence number in the Sequence Number field of the Binding Acknowledgement.