The first table focuses on the current classful routes being passed around by AS and the amount of gain CIDR would give *IF* we could aggregate as the AS level. It shows the number of nets per AS so we see who is announcing what in terms of BGP as well as what the number of CIDR nets would be advertised if we could aggregate at this level...
Tony,
Tony, On average each net learned by AS 690 is announced in 2.5 places. I think the range is typically 1-5 with the most common number being 2 (not sure on that). In any case, I think your assumption that we can aggregate at the AS level may be highly optimistic (at least for the near term - until we get far more sophisticated tools to track topology and aggregation implications). Of course, if CIDR either didn't prefer the more specific route but relied entirely on policy or punched holes in aggregates rather than overlap, this wouldn't be an issue, but that's the way CIDR works so it is an issue. It makes life much more interesting for Routing Authorities. :-) Curtis