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Re: Traffic per Prefix Length
>>>>> "bw" == Bill Woodcock <email@example.com> writes: >> does anyone collect stats that would facilitate the derivation of >> the number of packets forwarded per prefix length (per unit time) >> in the routing table or per prefix length range? > Anybody who's doing both Netflow and BGP table dumps can do that. > Of course, the corellation between the two isn't perfect, since you > may have prefix-length changes between snapshots. Another possibility would be to use one of the bucket-based accounting mechanisms (BGP Policy Accounting on Cisco and Riverstone, Destination Class Usage on Juniper): * define a route-map which maps announcements with different prefix lengths into different buckets * have the interfaces count traffic towards prefixes in each bucket automagically. The current Cisco implementation only has 8 buckets, which is a bit low because there are more than 8 prefix lengths in the real world. Juniper has 16 buckets which looks much better, and Riverstone has 25 which would cover even the absurd cases. Randy: You could also use this mechanism to count traffic that would potentially be affected by various kinds of route filters (by assigning a bucket instead of actually dropping the announcements). Some pointers to these features can be found on http://www.switch.ch/misc/leinen/snmp/monitoring/bucket-accounting.html -- Simon.