I assume you meant R4 not R1 here: > Assume that R1 is connected to another cloud of routers and > that traffic to networks A, B, and C will originate from this > other cloud.
And you didn't say what should happen if both the R1-R2-R3-R4 and R1-R7-R6-R5-R4 path are unavailable, so I will assume only traffic B and C are supposed to go through via the R1-R4 link. (Though it wouldn't make a big difference if traffic A needed to go through there, too.) I am also a bit uncertain why the routing requirements are stated "from R1's perspective", if they refer to the traffic that goes *to* R1. I'll assume this is just an oversight and you are not interested in how traffic *from* R1 will be routed. Having said that, my suggestion would be to run eBGP between - R4-R1 and filter out network A and increase the weight of network B, - R4-R3 and filter out network C, and - R4-R5 and filter out network C. R4 should run OSPF only on the interface towards the cloud, ie. R4 would talk only BGP towards R1, R3 and R5, and you would redistribute BGP into OSPF on R4. R3 and R5 could learn A, B and C via OSPF, I don't see why they would have to run BGP towards R1/R2/R6 (but they can if you want that). I think the above description pretty much nails down the configuration. If you really want specific configs, then tell me which part you are not clear about. Thanks, Zsombor p b wrote: > > > Lets go down another layer in your proposed BGP solution. > > The core topology will be along the lines of 5-10 routers > in a ring. Lets say 7 routers, R1, R2, R3, R4, R5, R6 and > R7 are connected in a p2p ring topology. Assume that there's > one or more direct connections between R1 and R4. > > R4 has 3 other interfaces for networks A, B, and C. Each is > a different service. > > Assume that R1 is connected to another cloud of routers and > that traffic to networks A, B, and C will originate from this > other cloud. > > The service routing requirements are as follows (from R1's > perspective): > > * traffic to A should go follow the R1-R2-R3-R4 and/or the > R1-R7-R6-R5-R4 path. > * traffic to B and C should follow the R1-R4 path > * when the link between R1 and R4 fails, B should be routed over > the R1-R2-R3-R4 and/or R1-R7-R6-R5-R4 path. Traffic to C should > stop. > > Provide some sample configs snipets for R1, R4 and an > intermediate > router which demonstrates how the proposed BGP solution would > support the policy requirements. > > Thanks > Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73849&t=73727 -------------------------------------------------- **Please support GroupStudy by purchasing from the GroupStudy Store: http://shop.groupstudy.com FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
