[c-nsp] Finding AS Edge Intefaces

[John Osmon]

On Mon, Mar 19, 2007 at 07:39:32AM -0800, Tony Tauber wrote:
> For a bunch of different purposes, it seems useful to be able to
> detect which interfaces represent the "edges" of an Autonomous System
> and which neighboring ASN lies across the link.
[...]
> Anyone have a programmatic way to derive these relationships either by
> examining the config (preferable) or the state of the router (CLI or
> SNMP) or a combination of the two?

Variations on a theme:
   http://www.nanog.org/mtg-0210/ppt/stephen.pdf

One (likely bad) idea that comes to mind is:
  - clogin -c 'sh ip bgp sum' | <snarf ASNs and neighbor addresses>
  - for each ASN snarfed:
    - for each neighbor address
      - clogin -c 'sh ip route <IP address>' | <snarf interface(s)>
      - spit out interfaces

I'm sure someone will come up with a better idea, rather quickly.
(Nothing seems to bring people out better then putting some trashy
psuedo-code out where others will find it.)