[c-nsp] High Availability PoP Design

[David Coulson]

Mark Tohill wrote:
> 1. I take it with such a simple topology, choosing which device is the
> root switch/bridge is unimportant. Is there any reason why the
> router(BVI) wouldn't act as root?

I would probably make sure two devices the same are the best preference
roots for STP, for a simpler topology change during a failure, but I've
never really had problems using it either way. I personally have it
setup with the switches as the STP root, as we have a number of
distribution switches talking STP to the core switches - The core
switches are a more natural central L2 device than the routers.

> 2. We have the following included in the config of our router:
> 
> !
> bridge 1 priority 0
> bridge 1 protocol ieee
> bridge 1 route ip
> !
> !
> bridge irb
> !
> I know we need the 'bridge irb' statement for sure. 
> 
> What is the 'bridge 1 route ip' doing exactly?

It allows the bridge to route IP traffic, otherwise all you have is a
switch. You need 'route ip' to be able to use BVIs. If you don't have
route ip enabled on the bridge, you can't do much with it :-)

David

-- 
David J. Coulson
email: david at davidcoulson.net
web: http://www.davidcoulson.net/