How trustworthy are existing BGP AS Paths?

>When Michnet border router advertises a route for a destination in
>UMnet, does it use the ASPath "MichnetASno UMnetASno" or just
>"MichnetASno" or "UMnetASno"?  (Perhaps UMnetASno = MichnetASno?).

It will use MichnetASno.  Since the Michnet router learns routes of UMnet
via IGP, it does not need to and does not know "UMnetASno".  So when you
redistribute IGP routes to BGP route, the routes are all marked with
MichnetASno as the origin.

>If it uses "MichnetASno", implementing policies at the AS level would
>not work. (Problem is at bad IGP-BGP interaction not becuase AS level
>policy implementation is inadequate.)

Yup.  

>Does this kind of IGP-BGP interaction happen in lots of places?

Well, there are messages to bgpd saying that they see a lot of routes with
different AS origin so it is perhaps not unusual. 

					--jessica



-------- Logged at  Thu Sep 29 22:33:50 MET 1994  ---------