North American Network Operators Group|
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Re: Disaster recovery using as-prepend?
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?