[c-nsp] Anycast services

[Tim Durack]

Okay, assuming I'm not doing per-packet load balancing (because that
breaks lots of things.)

I don't see why I can't run something simple like a web proxy anycast.
Even if I load balance per session, and have multiple equal cost paths
to the anycast address, I don't see how this would break.

But I have also never tried it...

Tim:>

On 5/18/06, Sam Stickland <sam_mailinglists at spacething.org> wrote:
> Hi,
>
> Comments inline.
>
> > -----Original Message-----
> > From: cisco-nsp-bounces at puck.nether.net [mailto:cisco-nsp-
> > bounces at puck.nether.net] On Behalf Of Tim Durack
> > Sent: 18 May 2006 16:20
> > To: cisco-nsp at puck.nether.net
> > Subject: [c-nsp] Anycast services
> >
> > The subject of Anycast DNS has raised my curiosity. Anyone tried
> > anycast of other services, such as a web proxy? Or is there a better
> > way to do this?
> >
> > I'm interested in this from a geographical redundancy perspective, as
> > opposed to purely clustering for load-balancing/redundancy.
>
> You can't ensure that packets routed to an Anycast address will always
> arrive at the same end point. They might arrive at a different node.
>
> Hence, you can't use Anycast for any kind of stateful service (e.g. TCP/IP).
> The correct approach to using it here would be to Anycast your DNS servers,
> and only have your DNS return entries for servers/cluster-groups that are
> known to be up.
>
> Sam
>
>