HA_7_2_15 - HA has more than one global IP address
Router
NUT
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--------+-------+-------+-------+-------+------- Link0
| | | |
R0 MN0 HA0 CN0
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--------+-------+----------------------- Link0X
|
MN0X
Link0 global 3ffe:501:ffff:100::/64 home link Link0X global 3ffe:501:ffff:1100::/64 foreign link R0 (Link0) global 3ffe:501:ffff:100::a0a0 ether 00:00:00:00:a0:a0 MN0 global 3ffe:501:ffff:100:200:ff:fe00:a2a2 home address CN0 global 3ffe:501:ffff:100:<TnDef.Link0_addr> link-local fe80::<TnDef.Link0_addr> ether <TnDef.Link0_addr> HA0 global 3ffe:501:ffff:100:200:ff:fe00:a3a3 global 3ffe:501:ffff:100:200:ff:fe00:b3b3 link-local fe80::200:ff:fe00:a3a3 ether 00:00:00:00:a3:a3 MN0X global 3ffe:501:ffff:1100:200:ff:fe00:a2a2 care-of address
Check Link0 routing tableNUT (Link0) HA0 CN0 MN0X | | | | | <-------------------- | Echo Request | --------------------> | Echo Reply | | | | | <------------ | | RS | ------------> | | RA (preference=10) | <---- | | | RA (preference=0xffff) | | | |
1. MN0X sends Echo Request 2. MN0X receives Echo Reply 3. CN0 sends RS 4. CN0 receives RA 5. HA0 sends RA
Check DHAADNUT (Link0) MN0X | | | <---- | HAAD Request | ----> | HAAD Reply | |
1. MN0X sends HAAD Request packet format is: ICMP_HAAD_request_message_format_from_MN_to_HA.gif 2. MN0X receives HAAD Reply packet format is: ICMP_HAAD_reply_message_format_form_HA_to_MN.gif
PASS: MN0X receives HAAD Reply
For each link on which a router provides service as a home agent, the router maintains a Home Agents List recording information about all other home agents on that link. This list is used in the dynamic home agent address discovery mechanism, described in Section 10.5. The information for the list is learned through receipt of the periodic unsolicited multicast Router Advertisements, in a manner similar to the Default Router List conceptual data structure maintained by each host for Neighbor Discovery [12]. In the construction of the Home Agents List, the Router Advertisements are from each other home agent on the link, and the Home Agent (H) bit is set in them.On receipt of a valid Router Advertisement, as defined in the processing algorithm specified for Neighbor Discovery [12], the home agent performs the following steps, in addition to any steps already required of it by Neighbor Discovery:o If the Home Agent (H) bit in the Router Advertisement is not set, delete the sending node's entry in the current Home Agents List (if one exists). Skip all the following steps.o Otherwise, extract the Source Address from the IP header of the Router Advertisement. This is the link-local IP address on this link of the home agent sending this Advertisement [12].o Determine the preference for this home agent. If the Router Advertisement contains a Home Agent Information Option, then the preference is taken from the Home Agent Preference field in the option; otherwise, the default preference of 0 MUST be used.o Determine the lifetime for this home agent. If the Router Advertisement contains a Home Agent Information Option, then the lifetime is taken from the Home Agent Lifetime field in the option; otherwise, the lifetime specified by the Router Lifetime field in the Router Advertisement SHOULD be used.o If the link-local address of the home agent sending this Advertisement is already present in this home agent's Home Agents List and the received home agent lifetime value is zero, immediately delete this entry in the Home Agents List.o Otherwise, if the link-local address of the home agent sending this Advertisement is already present in the receiving home agent's Home Agents List, reset its lifetime and preference to the values determined above.o If the link-local address of the home agent sending this Advertisement is not already present in the Home Agents List maintained by the receiving home agent, and the lifetime for the sending home agent is non-zero, create a new entry in the list, and initialize its lifetime and preference to the values determined above.o If the Home Agents List entry for the link-local address of the home agent sending this Advertisement was not deleted as described above, determine any global address(es) of the home agent based on each Prefix Information option received in this Advertisement in which the Router Address (R) bit is set (Section 7.2). Add all such global addresses to the list of global addresses in this Home Agents List entry.A home agent SHOULD maintain an entry in its Home Agents List for each valid home agent address until that entry's lifetime expires, after which time the entry MUST be deleted.