Failover solution using BGP

William Herrin herrin-nanog at
Wed Dec 31 02:29:32 UTC 2008

On Tue, Dec 30, 2008 at 7:08 PM, Naveen Nathan <naveen at> wrote:
> I have a client that would like to announce a /18 & /19 over BGP in
> Sacramento and LA, us being the second location in LA. Our location
> will be a failover location incase Sacramento goes down.
> They want failover for extreme cases when they're completly down in
> Sacramento. They have strict requirements so that traffic to their blocks
> should exclusively go to Sacramento or LA.

Announce from Sacramento normally.
Announce from LA with an AS prepend 3 or 4 deep.
GRE tunnel from LA back to Sacramento diverting the few packets which
insist on going to LA back to Sacramento during normal operation.

Or conditionally announce in LA based on a monitoring process which
watches Sacramento and deal with the extra complexity and longer
restoration time.

Bill Herrin

William D. Herrin ................ herrin at  bill at
3005 Crane Dr. ...................... Web: <>
Falls Church, VA 22042-3004

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