[nsp] conditional BGP config - help

[matthew zeier]

> 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

One of my backup transit providers in turn buys transit from Aleron.  I'm
trying to keep all traffic away from Aleron, however, certain broadband
providers (Cox) appear to also get transit from Aleron.  Occassionally,
Aleron appears to prefer my extra 10 AS prepends over my other upstream
providers.

Somehow I need to make them stop doing that.