[nsp] conditional BGP config - help

[Stephen J. Wilcox]

On Mon, 22 Mar 2004, Pete Templin wrote:

> matthew zeier wrote:
> > I have three transit providers - A, B, C - and want to setup conditional BGP
> > advertisements such that I only advertise my routes to C is both A and B are
> > down.
> 
> Alternate thought: advertise to C with several prepends (enough to get 
> to nearly zero traffic) all the time, perhaps also with the appropriate 
> community (for provider C) to request peer-level local preference to 
> minimize any reliance on the advertisement.  This way you can verify the 
> announcement at any time (i.e. through route-views.oregon-ix.net, etc.) 
> without having to wait for a double outage to test.

A word of caution, minimise your prepends, try one, try two.. bad things can 
happen when you overprepend your announcements, such as traffic preferring 
really bad paths during route leaks between peers etc

Steve

> 
> Just my $0.02,
> 
> pt
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