Subject: [Idr] BGP Optimal Route Reflection (BGP-ORR)

From: Russ White <[email-masked]>
Date: Fri, 08 Apr 2011 08:31:00 -0400

I support this draft for WG adoption. The solution proposed in section 3
seems fairly trivial given the widespread use of multiple SPFs, and the
tradeoff at the BGP level seems to be mostly about shifting processing
from one point in the network to another (as John as pointed out) --but
isn't this the point of virtualizing just about anything?

One nit:

==
In the case of a hierarchical IGP deployment where the client is in a
different level in the hierarchy to the route reflector, the route
reflector will compute IGP distance to the BGP nexthop from the Area
Border Routers (ABR) leading to the client in lieu of the route
reflector client itself, and use the shortest distance from these ABRs
to the nexthop.
==

It seems like this should be extended for IS-IS (?). Or are we assuming
L1/L2 routers can use the same terminology here?

For the solution outlined in section 4 --it seems to be fairly
computationally expensive today, but then again, SPF itself was fairly
computationally expensive when first used for OSPF/IS-IS --over time,
people have figured out how to reduce the computational expense to a
much more reasonable level. I would see this as more of a future
solution, but well worth documenting and working on.

Russ