> 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. _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
