[c-nsp] BGP sanity check

[Terry Baranski]

On Sat, 8 Dec 2012, Chuck Church wrote:

> RTR 1:
> BGP routing table entry for 209.209.144.0/20, version 23114388
> Paths: (2 available, best #1, table Default-IP-Routing-Table)
>  Not advertised to any peer
>  20115 1299 4323 10397
>    X.Y.39.3 from X.Y.39.3 (X.Y.39.3)
>      Origin IGP, metric 0, localpref 100, valid, internal, best
>  11456 7029 1299 4323 10397, (received & used)
>    216.215.152.1 from 216.215.152.1 (64.89.64.134)
>      Origin IGP, localpref 100, valid, external

RTR-1's best path is via RTR-2 due to shorter AS-PATH ("best #1"). So RTR-1
isn't going to advertise RTR-2's own path back to RTR-2.

-Terry