[c-nsp] LDPv6 Census Check

[Robert Raszuk]

> Well, we operate a single IS-IS L2 domain across 3 continents.
>
> We use what-I'd-call aggressive IS-IS detection and convergence timers,
> in addition to BFD and LFA/IP-FRR.
>
> We do very okay.
>

No doubt.

However one network is not equal the other. Especially SP/ISP network
requirements and any to any traffic patterns there are very different from
typical hub and spoke connectivity in the content or service serving
enterprise.

So if I am to put 1000 routers in the flat network, reduce OSPF timers and
inject all 1000 BGP next hops with label to all 999 PEs while I only need
999 PEs to ever reach 10 next hops I would keep to argue flat IGP is not
the right choice.

Moreover as one of the best industry IGP developer and expert I highly
respect stated very recently the end to end flooding time should stay below
200 ms. That is not your ICMP RTT ... that is time to receive the LSA/LSP
to local RE, install in LSDB and send it back. That determines the flooding
radius you should try not to exceed. And the time packet takes to even get
from LC to RE is very platform dependent as I am sure most of you know very
well :)

Cheers,
R.