Discovering AS Path confederation...

Thu Jul 26 20:51:45 UTC 2001

I just wanted to take a moment to thank everyone for helping me out with
this. I've a much better handle on the nature of the problem and likely
issues associated with it.

>From what I understand often the difference between the de jure path and
the de facto path are due to a combination of:
1) Interfaces belonging to one AS that sit in a router belonging to
another AS. 
2) A router not announcing an AS that sits behind it. 
3) Adminitsrative issues (eg, purely human failures to keep the ASes
updated properly).
4) Network topology (peer to peer links between ASes and such).
5) Hand of fate.

All in all I've come to the conclusion that my initial assumption (which
is that the BGP tables provide a relatively accurate macroscopic map of
network topology) is correct. I'll probably need to exapnd on this more
if I ever write a paper on my work but I'm still not sure I'm doing
anything really useful yet.

Chris Rapier
PSC/NCNE/NLANR