[124206] in North American Network Operators' Group
Re: IPv4 ANYCAST setup
daemon@ATHENA.MIT.EDU (Owen DeLong)
Fri Mar 26 13:09:51 2010
From: Owen DeLong <owen@delong.com>
To: Jeroen Massar <jeroen@unfix.org>
In-Reply-To: <4BACBCC8.3020409@spaghetti.zurich.ibm.com>
Date: Fri, 26 Mar 2010 10:04:41 -0700
Cc: nanog@nanog.org
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On Mar 26, 2010, at 6:55 AM, Jeroen Massar wrote:
> Max Larson Henry wrote:
>>
>>> has someone experience in anycast ipv4 networks (to support DNS)?
>>
>> "Never been done" "Dangerous" "TCP does not work" etc etc etc.
>>
>>
>> - Yes but as for DNS, anycast is essentially used for user requests
>> (UDP) not to perform zone transfer(TCP).
>
> Also that would work, unless you have a very unstable routing table
> that
> makes the node swap all the time.
>
It doesn't require an unstable routing table. There is a small set of
locations that could hit routers with multipath that may "balance"
the anycast packets down divergent paths.
Essentially, these are the topological midpoints between any two
(or more) anycast servers.
Owen
