Disaster recovery using as-prepend?

Christopher L. Morrow christopher.morrow at verizonbusiness.com
Fri Feb 17 21:25:16 UTC 2006

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?

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