[c-nsp] primary and backup routing with ISIS

[sthaug at nethelp.no]

> Can someone give me at hint how to configure routing in an MPLS network that carries VPN's.
> We are using ISIS as IGP and MBGP to announce VPN routes.
> The problem is, our PE-routers have one 10Gb and one 1Gb uplink on 5 sites. We would like to be sure that the traffic is routed via the 10G interface as primary and only use the 1G as backup. How is that done, and what is the best choice ??

The normal way of doing this would be to use IGP metrics - set the 1Gb
link to have a metric 10 times the 10 Gb link. Unfortunately Cisco has
not yet implemented "auto-cost reference-bandwidth" for IS-IS, so you
have to set the link metrics manually.

Oh yeah, you *really really* want to use IS-IS wide metrics.

Steinar Haug, Nethelp consulting, sthaug at nethelp.no