Hi, I'm in the process of deploying an anycast DNS service internally. We're on a pretty provider-like network, where we run MPLS to provide several network overlays for different services. iBGP is used to distribute routing information, and ISIS is used as IGP. In one of the VRFen we would like to place name servers using a common IP address. To get speedy network updates when outages occur we'll be using OSPF on the name servers to inject the routes into the IGP. The P/E router then redistributes the route into the right VRF. (the name server OSPF process is not aware of MPLS; it just talks to a router.)
So far so good. This works. Trouble is, we find that (untweaked) cost and metric are such that all nodes are equal. The last resort (peer router ID) gets invoked and all traffic goes to one single instance. Of course, when that instance falls off the net recalculation takes place and another node steps in, but I'd like true path lengths (IGP hop count) to influence more than iBGP (route-reflector-style) selection. Any clues? Oh, all-cisco, all ASR1000 series. All links GE. ~90 routers in IGP. -- Måns Nilsson primary/secondary/besserwisser/machina MN-1334-RIPE +46 705 989668 ... this must be what it's like to be a COLLEGE GRADUATE!!
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