I was wondering if anyone with experience in dealing with PCO in a Confederation, can share what they have done to mitigate it. I realize there are many ways to handle this, and I have read RFC 3345 as well as alot of stuff out there, but knowing what others have used in a actual operational environment would be interesting.

I plan to use a hub-spoke topology from a logical point of view for connecting sub-AS's. Also all the transit goes into the backbone/hub sub-AS (at least for now). I believe that alone would stop type II churn if I read correctly. It would seem you almost always need to raise the inter-sub-AS IGP metric above the intra-sub-AS IGP metric to ensure loop free topology.

Brian

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