North American Network Operators Group

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AS 701 local-pref answer.

  • From: David Barak
  • Date: Sun Dec 16 20:31:04 2001

Mike Leber wrote:

>If they set local pref for both peers and customers
>to 100 how do they
>ensure that the customer transit routes are
>announced to peers?

>The reason I ask this is because if a customer 
>announces a customer of
>theirs to you that a peer also has as a customer >you
will have equal
>length routes for the same destination AS.  While
>there are many ways to
>deterministicly prefer customer routes, local pref
>is the most common.

AS 701 always announces the best route, as their
routers know it.  Their average AS-path length is
under 2, so it doesn't seem to be a problem.  If a
customer of AS 701 wants to insure that his/her route
is advertised in all cases, s/he could send a
community which AS701 edge devices could use to
manipulate local-preference upward.  [this was covered
in a previous posting on this topic]  I leave it to
your imagination whether peers would be permitted to
do this.

-David Barak
I only speak for myself.
"Quis custodes ipsos custodiet?" - Juvenal

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