OSPF for IPv4 over IPv6 only?

[Ondrej Zajicek]

On Tue, Jan 30, 2024 at 12:20:41PM +0100, Sebastian Hahn wrote:
> Hi Nico,
> 
> > On 30. Jan 2024, at 10:32, Nico Schottelius via Bird-users <bird-users at network.cz> wrote:
> > OSPFv3 works fine on IPv6 and when creating two instances, one for IPv6
> > one for IPv4, things look correct. But how does OSFPv3 conceptually work
> > if the interface of the ospf area do not have IPv4 addresses themselves?
> > 
> > In the BGP case we can use "extended next hop on;" to use the IPv6
> > nexthop for IPv4, but I did not find a similar setting for OSPF to
> > accept IPv6 nexthops for IGP IPv4 addresses.
> > 
> > Is there a way to purely go IPv6 only and still relay stub network IPv4
> > information via an IPv6 only internal area?
> 
> I was facing the same issue before, and unfortunately, RFC 5838
> explicitly forbids IPv4 over IPv6 for OSPF.

Well, we could add 'extended next hop' option to override it, even if it
would be non-standard. It is rather small deviation.

I also thought about 'integrated-OSPFv3', where both IPv4 and IPv6 ranges
are propagated in one instance, but that seems like much larger deviation.

-- 
Elen sila lumenn' omentielvo

Ondrej 'Santiago' Zajicek (email: santiago at crfreenet.org)
"To err is human -- to blame it on a computer is even more so."