Re: DNS Anycast as traffic optimizer?

["Christopher L. Morrow" <christopher.morrow () mci com>]

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?