[88178] in North American Network Operators' Group
Re: Split flows across Domains
daemon@ATHENA.MIT.EDU (Christopher L. Morrow)
Tue Jan 24 10:45:12 2006
Date: Tue, 24 Jan 2006 15:38:55 +0000 (GMT)
From: "Christopher L. Morrow" <christopher.morrow@verizonbusiness.com>
In-reply-to: <8764o9aj8d.fsf@valhalla.seastrom.com>
To: "Robert E.Seastrom" <rs@seastrom.com>
Cc: Glen Kent <glen.kent@gmail.com>, NANOG list <nanog@merit.edu>
Errors-To: owner-nanog@merit.edu
On Tue, 24 Jan 2006, Robert E.Seastrom wrote:
>
>
> Glen Kent <glen.kent@gmail.com> writes:
>
> > For example, an ISP can learn two different equal cost routes to a
> > foo.com server via two different autonomous domains. It can thus split
> > different flows (based on src-dest IP, src-dest Port, TOS, etc) across
> > these two paths.
> >
> > Do operators currently do this?
> >
> > Folks can send me replies offline in case this constitues a "trade secret"!
>
> Works great with a flow-based router (or layer-three-switch-pronounced-
> 'crippled-router'). The downside, of course, is that you now have a
> flow-based router in your network, which has been shown to Not Work
> Well under other specified conditions (worm outbreaks come immediately
> to mind).
I could be mistaken, but this is also a feature in mbgp, effectively
loadsharing across two external paths. I presume the paths would have to
be completely equal all the way down to the router-id and (probably)
age-of-route ...
