Re: DNS Anycast as traffic optimizer?

[James <haesu () towardex com>]

On Wed, Sep 01, 2004 at 08:00:53PM +0000, Christopher L. Morrow wrote:
> 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.

Which begs the question.. is anyone doing this right now? I've been wondering
about the potential issues wrt anycasting tcp applications.. TCP sessions would
be affected negatively during a route change..

-J


-- 
James Jun                                            TowardEX Technologies, Inc.
Technical Lead                        Network Design, Consulting, IT Outsourcing
james () towardex com                  Boston-based Colocation & Bandwidth Services
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