Well I did a bit of digging at the sudden difference we are seeing. A lot of this points to different levels of aggregation at different points in the Internet. I took a dump from Bill's box at ?LA? and from the xara.net router I use at Mae-east and saw one immediate example of this. Here's the prefixes announced out of the 206.16/16 (belongs to CERFNET) block. First from xara.net (12 prefixes) --------------------------------- 206.16.0.0/16 in AS1740 206.16.192.0/18 in AS6077 206.16.96.0 in AS6332 206.16.97.0 in AS6332 206.16.98.0 in AS6332 206.16.99.0 in AS6332 206.16.102.0 in AS6332 206.16.105.0 in AS6332 206.16.106.0 in AS6332 206.16.111.0 in AS6332 206.16.112.0 in AS6332 206.16.113.0 in AS6332 Then Bill's router (59 prefixes) -------------------------------- 206.16.12.0 in AS4262 206.16.16.0 in AS4262 206.16.18.0 in AS1740 206.16.20.0 in AS1740 206.16.21.0 in AS1740 206.16.22.0 in AS1740 206.16.23.0 in AS1740 206.16.26.0 in AS1740 206.16.29.0 in AS1740 206.16.32.0 in AS4262 206.16.40.0 in AS4262 206.16.41.0 in AS4262 206.16.42.0 in AS4262 206.16.44.0 in AS4262 206.16.47.0 in AS4262 206.16.48.0 in AS4262 206.16.74.0 in AS4262 206.16.77.0 in AS4262 206.16.78.0 in AS4262 206.16.81.0 in AS4262 206.16.82.0 in AS4262 206.16.85.0 in AS4262 206.16.86.0 in AS4262 206.16.87.0 in AS4262 206.16.90.0 in AS1740 206.16.91.0 in AS1740 206.16.92.0 in AS1740 206.16.93.0 in AS1740 206.16.94.0 in AS4262 206.16.95.0 in AS1740 206.16.96.0 in AS1740 206.16.96.0 in AS6332 206.16.97.0 in AS6332 206.16.98.0 in AS6332 206.16.99.0 in AS6332 206.16.100.0 in AS1740 206.16.102.0 in AS6332 206.16.105.0 in AS1740 206.16.105.0 in AS6332 206.16.106.0 in AS6332 206.16.107.0 in AS1740 206.16.108.0 in AS1740 206.16.109.0 in AS1740 206.16.111.0 in AS6332 206.16.112.0 in AS6332 206.16.113.0 in AS6332 206.16.140.0 in AS4262 206.16.141.0 in AS4262 206.16.142.0 in AS4262 206.16.143.0 in AS4262 206.16.150.0 in AS1740 206.16.160.0 in AS1740 206.16.188.0 in AS1740 206.16.0.0/16 in AS1740 206.16.10.0/23 in AS4262 206.16.136.0/22 in AS4262 206.16.168.0/21 in AS4262 206.16.176.0/22 in AS4262 206.16.192.0/18 in AS6077 This is not to pick on CERFNET but just to highlight a problem of actually tracking the size of the routing table in general. This CERFnet case seems to be this way becuase it is a direct peer of Bill's box even though I can see no reason why the more specifics are needed. Looking a little more it seems a large amount of more specifics are being announced to Bill's boxe which aren't being announced to the xara.net router. Perhaps ISPs are taking more care at places like MAE-East with their outbound filters than they are at Bill's peering point even though Bill only has 6 active EBGP neighbors and the xara.net router has 39 ;-(. At this point I am pretty happy with using a well connected box at MAE-East as the point of reference. Bill, if you want to start your own your collection and make the data available feel free from your vantage piont. --Tony bmanning@ISI.EDU (Bill Manning) writes: * > * > > This is what I see from this neck of the woods: * > * > which is not very useful with no historical data. * > * * True enough. Perhaps tony would be willing * to share his methods so the results may be * comparable. I've got about two months worth * of data off sandbax. * * * -- * --bill