[j-nsp] Segment Routing Real World Deployment (was: VPC mc-lag)

[James Bensley]

On 5 July 2018 at 09:40, Mark Tinka <mark.tinka at seacom.mu> wrote:
>
> In our case, we have different boxes from Cisco, each with varying support
> for SR. This makes things very tricky, and then we need to also throw in our
> Juniper gear. For me, the potential pain isn't worth the hassle, as we are
> not suffering in any way that makes the move to SR overly compelling.

Previously I mentioned that we build out greenfield regional networks
but the core that links them is of course brownfield. We have the same
problem there, mixed Cisco Juniper and a reasonable amount of variance
then within those two vendor selections. As previously mentioned,
there are no requirements that we can only fix with SR and the
benefits aren't worth the truckroll to get SR capable kit and code
everywhere.

> - Go IPv6 native: If using ISIS as the IGP we should be able to go
> IPv4 free (untested and I haven't research that much!).
>
>
> For me, this is the #1 use-case I was going for; to be able to natively
> forward IPv6 packets inside MPLS, and remove BGPv6 from within my core.
>
> I had a discussion about this with Saku on NANOG:
>
>     http://seclists.org/nanog/2018/May/257
>
> Where we left things was that while the spec allows for signaling of IPv6 in
> the IGP, there is no clear definition and/or implementation of MPLSv6 in the
> data plane today.

Ah, I remember that thread. It became quite long and I was very busy
so I lost track of it. Just read through it. I also looked at LDPv6 a
while back and saw it was not well supported so passed. For us 6PE
(and eventually 6vPE as we move to Internet in a VRF) "just works".
IPv6 native in SR isn't actually enough of a reason for me to migrate
to it I don't think.

You mentioned in the NANOG thread that you wanted to remove BGP from
your core - are you using 6PE or BGP IPv6-LU on every hop in the path?
I know you are a happy user of BGP-SD so I guess it's Internet in the
GRT for you?

Cheers,
James.