Eduardo,Remember that the input to the aggregation step is the Local RIB. Prefixes to be aggregated need to share the same next hop (not in the BGP NEXT_HOP sense necessarily, but in the actual what-you-put-in-the- forwarding plane sense). The AS_PATH is irrelevant to the aggregation step. This is because the aggregation is never exposed outside the local router. Indeed, modulo the "creating additional routable space" issues introduced by "Type 4" of the draft it should be impossible for an outside observer to even tell if FIB aggregation is in use or not.
The whole thing is orthogonal to what goes on in the control plane.As for the evaluation methodology, Lixia or one of her co-authors will have to address that.
--John On Nov 11, 2009, at 2:26 PM, Eduardo Ascenço Reis wrote:
Hi, Regarding FIB Aggregation draft (draft-zhang-fibaggregation-02.txt), prefixes that would be aggregated share the same NEXT_HOP and AS_PATH attributes. Is that correct? From Lixia presentation I got that the evaluation methodology extracted NEXT_HOP from AS_PATH information (Route Views Archive Base). Thanks, -- Eduardo Ascenço Reis