[SPAM] Re: [SPAM] Re: OSPF vs ISIS - Which do you prefer & why?

Mark Tinka mark.tinka at seacom.mu
Fri Nov 11 07:11:32 UTC 2016


On 11/Nov/16 08:22, sthaug at nethelp.no wrote:

>
> We have a similar use case, and we run BGP on Quagga. Works great.
> Haven't seen a need for either IS-IS or OSPF on Quagga yet.

Two reasons for us:

  * IGP metrics in the IGP will determine latency-based decisions. I
    know BGP can infer the IGP metric, but we are just avoiding
    situations where this could be non-deterministic due to other
    BGP-things.

  * BGP occurs at a much higher layer in the network stack. We run the
    Anycast servers in the IGP domain because that is at a much more
    basic layer. If BGP fails, we don't want to have problems logging
    into our routers because it took TACACS+ with it. There have been
    times when BGP has run into issues but the IGP has remained alive.
    Via a jump host (and OoB, of course), we were able to maintain
    connectivity to the network to fix it because those servers are in
    the IGP domain.

Mark.




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