North American Network Operators Group
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Re: ultradns reachability

  • From: Joe Abley
  • Date: Fri Jul 02 11:20:51 2004 
On 2 Jul 2004, at 10:43, Leo Bicknell wrote:


Note in the later pages what happens to particular servers under
packet loss.  They all start to show an affinity for a subset of
the servers.  It's been said that by putting some non-anycasted
servers in with the anycasted servers what can happen is if the
anycast has issues many things will "latch on" to the non-anycasted
servers and not go back even when the anycast is fixed.
In my opinion, the primary purpose of anycast distribution of nameservers is reliability of the service as a whole, and not performance. Being able to reach a server is much more important than whether you can get a reply from a particular server in 10ms or 500ms.

So, I think the issue you mention (which is certainly mention-worthy) is a much smaller problem than the apparently observed problem of all nameservers in the NS set being unavailable.


Joe