On (2013-01-23 09:38 +0100), Adam Vitkovsky wrote: > What would be the best trigger for a default route advertisement either from > the edge(PE) routers or core(RR) routers. > -eBGP peer's interface might be reachable though the eBGP session might be > down. > -ability or inability to see a single route (or couple of routes for that > matter), might not reflect the ability of a particular edge to perform > full-table routing.
In this case you can have your cake and eat it. ip route 0.0.0.0 0.0.0.0 8.8.8.8 ip route 0.0.0.0 0.0.0.0 ASBR_ANYCAST 200 Or you could even have: ip route 0.0.0.0 0.0.0.0 important_inet1 ip route 0.0.0.0 0.0.0.0 important_inet2 190 ip route 0.0.0.0 0.0.0.0 important_inetN 199 ip route 0.0.0.0 0.0.0.0 ASBR_ANYCAST 200 (ASBR_ANYCAST, is some (same) host/32 route in loopN in all of your ASBR, so always resolves to closest ASBR up.) So as long as important_inetN is advertised, you are using it, which guarantees that edge is alive and is receiving at least this prefix. If non of important_inetN is advertised, you can fallback to anycast ASBR edge, hoping the edge works. But frankly, I'd opt for having just one important_inetN, some reasonable stable destination. If that is gone, just fall back to closest ASBR Anycast. -- ++ytti _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
