2014-04-07 18:29 GMT+02:00 Ondrej Zajicek <santiago@crfreenet.org>:
Hello
That is because only resolvable routes are considered (RFC 4271 9.1.2.1), main reason for that condition is to eliminate routes whose bgp_next_hop cannot be resolved using IGP, it also affects routes whose bgp_next_hop is resolved to a unreachable/blackhole/prohibit route.
In your case, it could be fixed by adding higher protocol preference (different attribute than bgp_local_pref, currently 100) to b_rr1.
Unfortunately increasing the preference of the b_rr1 session is not an option as from my understanding it would completely eliminate the bgp route selection rules (All routes learned via b_rr1 are preferred over b_dtag1). Is there any other solution for this besides doubling the iBGP connections (adding seperate blackhole only sessions with higher preference)?