HA_2_6_10 - Inalid sequence number A=0 SN(1st=15, 2nd=14)
Router
MN1Y
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--------+-------+------- Link1Y
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R1X MN1X
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--------+-------+-------+------- Link1X
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R1
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--------+-------+----------------------- Link1
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NUT
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--------+-----------------------+------- Link0
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MN0
Link0 global 3ffe:501:ffff:100::/64 home link Link1 global 3ffe:501:ffff:101::/64 foreign link Link1X global 3ffe:501:ffff:1101::/64 foreign link Link1Y global 3ffe:501:ffff:2101::/64 foreign link R1 (Link1) global 3ffe:501:ffff:101::a1a1 ether 00:00:00:00:a1:a1 MN0 global 3ffe:501:ffff:100:200:ff:fe00:a2a2 home address MN1X global 3ffe:501:ffff:1101:200:ff:fe00:a2a2 care-of address MN1Y global 3ffe:501:ffff:2101:200:ff:fe00:a2a2 care-of address
Check Link1 routing tableNUT (Link0) MN1X MN1Y | | | | <---- | | Echo Request | ----> | | Echo Reply | | | | <------------ | Echo Request | ------------> | Echo Reply | | |
1. MN1X sends Echo Request 2. MN1X receives Echo Reply 3. MN1Y sends Echo Request 4. MN1Y receives Echo Reply
home registrationNUT (Link0) MN1X | | | <---- | BU (SN=15, A=1, lifetime=0x0010) (SPI=0x101) | ----> | BA (SN=15) (SPI=0x102) | | | <---- | Echo Request w/ HaO | ----> | Echo Reply w/ RH | |
1. MN1X sends BU 2. MN1X receives BA 3. MN1X sends Echo Request w/ HaO 4. MN1X receives Echo Reply w/ RH
Check sequence number comparisonNUT (Link0) MN1Y | | | <---- | BU (SN=14, A=0, lifetime=0x0010) (SPI=0x101) | ----> | BA (status=135, SN=15) (SPI=0x102) (*1) | | | <---- | Echo Request w/ HaO | ----> | BE (status=1) (*2) | |
1. MN1Y sends BU packet format is: Binding_Update_message_format_from_MN_to_HA_ESP.gif 2. MN1Y receives BA (*1) packet format is: Binding_Acknowledgement_message_format_from_HA_toMN_ESP.gif 3. MN1Y sends Echo Request w/ HaO 4. MN1Y receives BE (*2) packet format is: Binding_Error_message_from_HA_to_MN.gif
(*1) PASS: MN1Y receives BA (*2) PASS: MN1Y receives BE
9.5.1 Receiving Binding UpdatesPackets containing a Home Address option MUST be dropped if the given home address is not a unicast routable address.Mobile nodes can include a Home Address destination option in a packet if they believe the correspondent node has a Binding Cache entry for the home address of a mobile node. Packets containing a Home Address option MUST be dropped if there is no corresponding Binding Cache entry. A corresponding Binding Cache entry MUST have the same home address as appears in the Home Address destination option, and the currently registered care-of address MUST be equal to the source address of the packet. These tests MUST NOT be done for packets that contain a Home Address option and a Binding Update.If the packet is dropped due the above tests, the correspondent node MUST send the Binding Error message as described in Section 9.3.3. The Status field in this message should be set to 1 (unknown binding for Home Address destination option).
Before accepting a Binding Update, the receiving node MUST validate the Binding Update according to the following tests:o The packet MUST contain a unicast routable home address, either in the Home Address option or in the Source Address, if the Home Address option is not present.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.If the receiving node has no Binding Cache entry for the indicated home address, it MUST accept any Sequence Number value in a received Binding Update from this mobile node.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 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.