Looking for geo-directional DNS service

Tue Jan 15 17:50:00 UTC 2008

On Jan 15, 2008, at 12:00 PM, Bill Woodcock wrote:
>      On Tue, 15 Jan 2008, Hank Nussbacher wrote:
>> The Ultradns (now Neustar) Directional DNS service is based on
>> statically defined IP responses at each of their 14 sites so there
>> is no proximity checking done.
>
> Yes, and that's how anycast works: it directs traffic to the
> _topologically nearest_ server.  So as long as there's a DNS server
> topologically near your data server, your users will get the  
> topologically
> nearest of your servers.  Which is why so many content folks _do_ roll
> their own: to ensure fate-sharing between the DNS traffic which
> effectively selects the data server, and the eventual data traffic.
>
> If you're doing things on the Internet, instead of the physical world,
> topological distance is presumably of much greater interest than  
> whatever
> geographic proximity may coincidentally obtain.

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?

-- 
TTFN,
patrick