On Friday, January 02, 2015 11:03:21 PM Daniel Rohan wrote:
Also think physical topologies like ethernet rings. Where's the RR go in this topology?
In these topologies, I've been playing with having the RR's in the core (i.e., on the other end of the PE Aggregation routers terminating the ring) and running the iBGP sessions between the Metro-E Access switches and the RR's. As the RR's are MPLS-free (but the Metro-E Access switches [particularly Cisco] still assign MPLS labels to each IGP route), we cobble together a combination of hop-by-hop IP forwarding + MPLS forwarding fu to get traffic to where it needs to go without involving the PE Aggregation routers in the routing toward the Metro-E Access switches (i.e., 0/0 and ::/0 + a few more specifics come from the RR's). Been working with this routing topology for MPLS rings since 2009. It seems to hold up... Mark.