[73714] in North American Network Operators' Group
Re: DNS Anycast as traffic optimizer?
daemon@ATHENA.MIT.EDU (Christopher L. Morrow)
Wed Sep 1 16:03:53 2004
Date: Wed, 01 Sep 2004 20:00:53 +0000 (GMT)
From: "Christopher L. Morrow" <christopher.morrow@mci.com>
In-reply-to: <413623F2.1080909@fastclick.com>
To: Steve Francis <sfrancis@fastclick.com>
Cc: Bill Woodcock <woody@pch.net>, nanog@merit.edu
Errors-To: owner-nanog-outgoing@merit.edu
On Wed, 1 Sep 2004, Steve Francis wrote:
>
> Christopher L. Morrow wrote:
>
> >If I read your original request correctly you were planning on:
> >1) having presence in multiple datacenters (assume multiple providers as
> >well)
> >2) having a 'authoritative' DNS server in each facility (or 2/3/4
> >whatever per center)
> >3) return datacenter-1-host-1 from datacenter-1-authserver-1,
> >datacenter-2-host-2 from datacenter-2-authserver-1, and so forth.
> >
> >This isn't really 'anycast' so much as 'different A records depending on
> >server which was asked'
> >
> >
> Well, there'd be one NS record returned for the zone in question. That
> NS record would be an IP address that is anycasted from all the datacenters.
> So end users (or their DNS servers) would all query the same IP address
> as the NS for that zone, but would end up at different datacenters
> depending on the whims of the anycasted BGP space.
Hmm, why not anycast the service/application ips? Having inconsistent DNS
info seems like a problem waiting to bite your behind.
>
> > I suspect you'd really also introduce some major
> >troubleshooting headaches with this setup, not just for you, but for your
> >users as well.
> >
> >
> I don't doubt that. :-)
>
which I'd think you'd want to minimize as much as possible, right?
