[c-nsp] LDPv6 Census Check

Mark Tinka mark.tinka at seacom.mu
Fri Jun 12 15:26:41 UTC 2020

On 11/Jun/20 19:19, Saku Ytti wrote:

> The demand is, we need tunneling, then the question is what are the
> metrics of a good tunneling solution. By answering this honestly, MPLS
> is better. We could do better surely, but IP is not that.

One unexpected benefit, I will say, with going native LDPv6 is that
MTR's for IPv6 destinations no longer report packet loss on the
intermediary core routers (CRS-X).

I know this was due to the control plane, and nothing to do with the
actual data plane, but it was always a tool explaining to customers why
MTR's for IPv4 destinations have 0% packet loss in our core, while IPv6
ones have 30% - 50% (in spite of the final end-host reporting 0% packet

Since going LDPv6, IPv6 traffic is now label-switched in the core, in
lieu of hop-by-hop IPv6 forwarding. The unforeseen-but-welcome side
effect is that customer packet loss MTR's for IPv6 destinations that
traverse the CRS-X core are as 0% as they are for IPv4 (even though we
haven't yet removed BGPv6 from the core due to IOS XE platforms that
don't yet run LDPv6).

One less trouble ticket to have to explain for our NOC; I'll gladly take

As my Swedish friend would say, "That gives me an avenue of pleasure and
joy" :-).


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