V4 via V6 and IGP routing protocols

Mon Apr 4 12:10:11 UTC 2022

On 4/4/22 02:55, Dave Taht wrote:

> it was how hard adding source specific routing to isis turned out to
> be that turned me.
> At the time I needed simple means to get ipv6 working on multiple
> consumer uplinks.

I suppose the presence of MPLS (and SR) for many operators is probably 
why this use-case was not pushed hard by that community in the IGP.

> I'm sad to hear that those two still have to co-exist. I'd given up on
> how static
> both routing protocols had become in light of my wireless requirements way
> back then, also memory requirements. Babel had turned out to be the only
> way to get teeny routers to route a few thousand ipv6 routes as well
> as ipv4 over wifi mesh networks.

Given a good number of boxes are now based on x86 platforms, control 
plane management of the "classic" IGP's is not a major drama for a few 
thousand entries. One is more likely to run into FIB issues (as we have 
done).

It's possible that at least one operator is using OSPFv3 for both IPv4 
and IPv6, but they haven't come out publicly to announce this :-).

We (and many others) have been running IS-IS for both IP protocols, 
without major issue over the years.

> I figured it had made zero penetration outside of that world despite
> our efforts to get it into frr, bird, etc.

You're certainly right about that one...

Mark.