nanog mailing list archives

Re: Service Providers behaviour for dual homed enterprises


From: William Herrin <bill () herrin us>
Date: Thu, 24 Sep 2015 09:21:02 -0400

On Wed, Sep 23, 2015 at 5:38 PM, Jason Bullen <jmbullen21 () gmail com> wrote:
So if my research is correct, the internet prefers Verizon UNLESS they are
a direct AT&T customer then they would use the AT&T circuit.
Is this a standard practice that I should assume to encounter?

Hi Jason,

That's normal. Verizon does it too. Both have "community" tags which
you can attach to your route advertisement. Each will have one that
indicates they should give external routes the same "local pref" as
the route you announce to them. Tagging your route announcement with
the proper community will cause them to route based on AS path length
as you expect.

Welcome to the little gotchas of using BGP.

Regards,
Bill Herrin

-- 
William Herrin ................ herrin () dirtside com  bill () herrin us
Owner, Dirtside Systems ......... Web: <http://www.dirtside.com/>


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