If “policy routing” reminds you of nightmarish spaghetti solutions of hop-by-hop route-maps, read my latest IP Corner article, Scalable Policy Routing. It describes how you can use a distance vector routing protocol (BGP is used in the article, but you could do the same with EIGRP or even RIP) to solve common policy routing problems in a highly scalable way.
Ivan Pepelnjak, CCIE#1354, is the chief technology advisor for NIL Data Communications. He has been designing and implementing large-scale data communications networks as well as teaching and writing books about advanced technologies since 1990. See his full profile, contact him or follow @ioshints on Twitter.