It should be the unicast source address of the RUT on Link0.
But moving forward, when we revise RFC 3775, I think the anycast address should also be allowed to be used as the source address on the DHAAD reply message. There used to be a restriction earlier that an anycast address shouldn't be used as the source address, but was removed recently. I forget which spec. Vijay Nicolas Dichtel wrote:
Hi, I've a question about source address selection in HAAD Reply message. Here is the topology: MN1X | --------+-------+--------------- Link1X | R1 | --------+-------+----------------------- Link1 | RUT | - - - - + - - - - - - - - - - - - - - - Link0 RUT is a Home Agent and the Home Link is Link0. Let's call RUT(Link1) the unicast address sets of the interface connected to Link1 and RUT(Link0) the unicast address sets to the interface connected to Link0.MN1X sends a HAAD Request message to its home agent (RUT). The destination address of this message is an anycast address. When RUTsends the HAAD Reply message, which source address must be used ? RUT(Link1) or RUT(Link0) ? RFC3775 Section 10.5 just says: "A home agent receiving a Home Agent Address Discovery Request message that serves this subnet SHOULD return an ICMP Home Agent Address Discovery Reply message to the mobile node with the Source Address of the Reply packet set to one of the global unicast addresses of the home agent." Following RFC3484, I think that rules #5 (Prefer outgoing interface) in Section 4 is reached. But, there is some cases, like for ICMP ECHO Reply (RFC 4443 Section 4.2), where source address must be the destination address of the request message. In our case, the destination address is an anycast address (assigned to the interface attached to Link0) and, following the RFC2526 Section 1, the packet is delivered to RUT(Link0): "The anycast address may be assigned to one or more network interfaces (typically on different nodes), with the network delivering each packet addressed to this address to the "nearest" interface based on the notion of "distance" determined by the routing protocols in use." So, it's not clear which source address must/can be used. For example, the TAHI tests suite expects the use of RUT(Link0). Regards, Nicolas _______________________________________________ Mip6 mailing list [EMAIL PROTECTED] https://www1.ietf.org/mailman/listinfo/mip6
-------------------------------------------------------------------- IETF IPv6 working group mailing list [email protected] Administrative Requests: https://www1.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
