09-14-2017 09:49 AM - edited 03-08-2019 12:02 PM
I have always wondered: Why would you want to also specify the link-local address of the next hop in an IPv6 static route if you are already specifying the outgoing interface, which is sufficient by itself?
09-14-2017 10:36 AM - edited 09-14-2017 10:43 AM
In short, I think it has to do with Neighbor discovery's ICMP redirect messages.
A device must be able to determine the link-local address for each of its neighboring devices in order to ensure that the target address (the final destination) in a redirect message identifies the neighbor device by its link-local address. For static routing, the address of the next-hop device should be specified using the link-local address of the device; for dynamic routing, all IPv6 routing protocols must exchange the link-local addresses of neighboring devices.
Edit:
Mark Holm posted this way back which is along the same lines: https://learningnetwork.cisco.com/thread/83948
Im unsure if this is the only reason though.
09-14-2017 10:46 AM
09-14-2017 12:42 PM
Hi Nezhad,
This does not work on an interface that requires neighbor discovery (ND). For IPv4 we have proxy ARP, that allows the router to reply to a ARP query for a destination that is not on the local subnet. There is currently no equivalent for IPv6 (proxy ND).
Regards,
09-23-2017 07:15 PM
what doesn't work? specifying only the outgoing interface? but it does. It's supposed to. You don't need to specify the link local address of the next hop necessarily.
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