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

[Mark Tinka]

On 7/Jul/18 13:03, James Bensley wrote:

> 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.

LDPv6 implementation in IOS XR was a bit spotty 2 years. After our next
round of code upgrades later this year on Cisco and Juniper, I'll see
where we are and target to get LDPv6 going before we close out 2018.


> 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?

I removed BGPv4 from the core back in 2008 (previous job). So all IPv4
traffic is forwarded inside MPLS, purely label-switched in the core.
This is just simple LDP signaling + MPLS forwarding toward a BGP next-hop.

For IPv6, as LDPv6 is not yet fully deployed around the network, we are
still carrying BGPv6 in the core. That is normal hop-by-hop IP
forwarding. We don't like 6PE or anything like that because it still
depends on IPv4; I'd much rather run both protocols ships-in-the-night.
That way, if one of them were to break, chances are the other should
still be good.

We don't do Internet in a VRF. Seems like too much headache, but that's
just me, as I know it's a very popular architecture with many operators
out there. We carry all routing in global, as you rightly point out,
making heavy use of iBGP and communities to create excitement :-).

We love BGP-SD -- it means we can deliver the same types of services on
all platforms in all sections of the network, be it in the data centre
or Metro, or be it on a big chassis or a tiny 1U router, or be it in a
large or small PoP.

Mark.