Except Hank is asking for true topological distance (latency / throughput / packetloss).
Anycast gives you BGP distance, not topological distance.
Say I'm in Ashburn and peer directly with someone in Korea where he has a node (1 AS hop), but I get to his node in Ashburn through my transit provider (2 AS hops), guess which node anycast will pick?
Ashburn and other major network meet points are oddities in a very complex network. It would be fair to note that anycast is likely to be reasonably effective if deployed in a manner that was mindful of the overall Internet architecture, and made allowances for such things. Anycast by itself probably isn't entirely desirable in any case, and could ideally be paired up with other technologies to "fix" problems like this. I haven't seen many easy ways to roll-your-own geo-DNS service. The ones I've done in the past simply built in knowledge of the networks in question, and where such information wasn't available, took "best guess" and then may have done a little research after the fact for future queries. This isn't as comprehensive as doing actual latency / throughput / pl checking. ... JG -- Joe Greco - sol.net Network Services - Milwaukee, WI - http://www.sol.net "We call it the 'one bite at the apple' rule. Give me one chance [and] then I won't contact you again." - Direct Marketing Ass'n position on e-mail spam(CNN) With 24 million small businesses in the US alone, that's way too many apples.