Using multiple processes might provide a way to implement policy at the link level. Typically, when one thinks of policy, one thinks of BGP. But what if your policy requires the ability to control what traffic can or can't go over a particular link? For example, consider two routers, that are interconnected by a direct link and a N-hop L3 path. Suppose traffic types A and B should typically go over the direct link but, if the direct link fails, traffic type A should be routed over the N-hop L3 path and traffic type B should not be forwarded.
I don't believe there's a way to get this level of policy from a single OSPF process or a single OSPF process coupled with BGP. However, if you run multiple OSPF processes, say one for each interesting traffic type, and if you use BGP to set a network's next-hop to match the right OSPF RID, and for each link define a sub-interface (or not) for each OSPF process, then I think the above routing requirements might be supported. MPLS might work here, but I'm not sure. Suppose you have certain types of traffic that Zsombor Papp wrote: > > What are you trying to achieve with these ~3 OSPF routing > processes? > > Thanks, > > Zsombor > > p b wrote: > > > > > > I'm considering a routing architecture where devices in the > > network would run ~3 OSPF routing processes. > > > > I think each routing process will be handling the routing > > of non-overlapping address blocks and thus the routes they > > give to the forwarding table should be disjoint. > > > > However, I'd like to understand what happens if two processes > > each were to provide the same prefix to the forwarding table. > > Specifically, what are the rules to determine which prefix > > is put into the routing table? > > > > Also be interested in any learnings folks might have had when > > they've run multiple OSPF processes. > > > > Thanks > > Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=73789&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
