[Babel-users] cornercase issue (link sensing)

[Juliusz Chroboczek]

Sorry to follow-up on myself.

> In version 2, the neighbour is identified with the link-local IPv6
> address, so multiple adjacencies between the same two nodes are okay.

Just to be clear: there is no issue at all with conflicting routable
addresses.  If two neighbours on the same link have the same IPv4
address, or the same globally routable IPv6 address, Babel will
distinguish the two since they should have distinct link-local
addresses.

However, IPv4 routing might not be optimal.  For IPv6 routing, the next
hop is set to the link-local address, so everything will be fine.  For
IPv4 routing, the next hop will be set to the advertised IPv4 address,
and which of the two neighbouring interfaces will be chosen for routing
will be non-deterministic (it'll be the one that answers first to an ARP
query).

Shall we migrate to IPv6 now?

                                        Juliusz