[j-nsp] BFD Distributed Mode for IPv6

[James Bensley]

On Tue, 2 Oct 2018 at 21:46, Mark Tinka <mark.tinka at seacom.mu> wrote:
> On 2/Oct/18 21:13, James Bensley wrote:
>
> I presume that if one were to run MT-ISIS there would be no impact to IPv4?
>
>
> We already run MT for IS-IS. I consider this as basic a requirement as "Wide Metrics".

I'm not sure about Junos but IOS-XR can run wide metrics in ST-ISIS so
I wasn't going to assume MT :)

> However, the issue here is BFD sees the whole of IS-IS as a client. So if BFD has a moment, it will signal its client (IS-IS), regardless of whether the moment was for IPv4 or IPv6.

Ah, yeah, that is a bummer :(

> I imagine that re-running adjacencies and SPF just for the IPv6 topology would be a vendor-specific solution to the problem. However, wouldn't it just be easier to support BFD for IPv6 in the PFE as Juniper already does for IPv4?
>
> I'd be interested to know if BFD works OK if you use public IPv6
> addresses for IS-IS adjacencies (although it's a waste of IPs, I'd
> still be curious).
>
>
> Interesting.
>
> What I do know is that if you are running BFD for static IPv6 routes, it runs in the PFE. But if the routes are learned via an IGP (IS-IS or OSPFv3), it can only run in the RE.

That is interesting.

Cheers,
James.