IPv4 next-hops over IPv6

[Tore Anderson]

* Chris Malayter
> Probably better question.  Is RFC5549 supported by BIRD?

Yes, RFC 8950 is on the list of supported standards, and can be 
configured with the «[require] extended next hop» configuration option.

https://bird.network.cz/?get_doc&v=20&f=bird-6.html#ss6.4

No reason whatsoever this wouldn't work as well on an IX as it would on 
any other Ethernet link. IX-es aren't that special, except maybe needing 
to cater to customers running BGP implementations not updated since the 
1990s.

Tore