[dns-operations] Anycast vs. unicast NS

David Miller dmiller at tiggee.com
Mon Mar 21 16:09:21 UTC 2011

On 3/21/2011 10:54 AM, Simon Munton wrote:
>> 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?
> There is rarely only one reason to deploy any particular technology, 
> and availability is a very significant benefit of anycast - however, 
> there [is / was / has been] also a general perception that the client 
> is [always / usually] sent to the "network nearest" node, which isn't 
> [always / usually / probably] the case. That was the point of the 
> discussion.
> Stephane pointed out that sometimes the results (of which node you are 
> sent to) can be surprising, & I agreed.
> However, I would think its pretty clear that sending the client to the 
> network nearest node would be a "nice to have" feature, and I thought 
> it would be an interesting topic to discuss.

Sending the client to the 'network-wise' nearest node is more than a 
"nice to have", it is necessary to gain many of the ancillary benefits 
of anycasting a service.

David Miller
Tiggee LLC
dmiller at tiggee.com

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