[88782] in North American Network Operators' Group
Re: Disaster recovery using as-prepend?
daemon@ATHENA.MIT.EDU (Christopher L. Morrow)
Fri Feb 17 16:36:32 2006
Date: Fri, 17 Feb 2006 21:25:16 +0000 (GMT)
From: "Christopher L. Morrow" <christopher.morrow@verizonbusiness.com>
In-reply-to: <Pine.WNT.4.63.0602171554180.2736@jvc>
To: Todd Vierling <tv@duh.org>
Cc: Warren Kumari <warren@kumari.net>,
"Christopher J. Pilkington" <christopher.j.pilkington@gmail.com>,
nanog@merit.edu
Errors-To: owner-nanog@merit.edu
On Fri, 17 Feb 2006, Todd Vierling wrote:
>
> On Thu, 16 Feb 2006, Warren Kumari wrote:
>
> > If your primary is connected to ISP_A and the backup is connected to ISP_B,
> > customers connected to ISP_B MAY still flow to your backup DC (ISP_B will
> > probably set local preference on all customer routes - you should be able to
> > override this behavior with communities but not all providers support this (or
> > honor it 100% of the time!))
>
> And in addition to that, even multihomed customers of ISP_B may choose the
> prepended route for a number of different reasons; for instance, ISP_B might
> be a cheaper pipe for them, or there may be a smart-ish routing device or
> scheme in play that overrides normal BGP decision making.
I might be crazy, but couldn't you just prepend the route enough to
effectively poison it at ingress to 'backup-isp' ? so they kept chosing
the remote path and never really accept the route from local until the
remote path is gone?
