[dns-operations] Anycast vs. unicast NS

Joe Abley jabley at hopcount.ca
Mon Mar 21 14:37:27 UTC 2011

On 2011-03-21, at 09:29, Simon Munton wrote:

> On 20/03/2011 01:00, Stephane Bortzmeyer wrote:
>> Anycast is great for reliability and resiliency, but it does not
>> optimize the RTT.
> Our experience is the same - see my previous post on this thread on 18th

Zones containing RRSets with non-ludicrous RTTs have their data cached in (hopefully) sensible places close to end-users, and end-user performance relates to that cached data most of the time, not the authoritative data.

My reason for distributing authority-only service using anycast is to improve availability. If your reason is to reduce the transaction time for the tiny proportion of queries that land on the authority servers, is that sensible?

> One time we had queries from Russia ending up in Tokyo, going past our nodes in RIPE, London, Ashburn & LA - so not even the shortest route to Tokyo!
> We fixed it, and now have nodes in Moscow & StP
> is the only answer to this more & more & more nodes?

I think the answer depends on your question. What are you trying to achieve?


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