Preferring peers over customers [was: Do Not Complicate Routing Security with Voodoo Economics]

Jared Mauch jared at
Mon Sep 5 14:26:18 UTC 2011

On Sep 4, 2011, at 9:18 PM, Patrick W. Gilmore wrote:

> I would like the large networks of the world to state whether they prefer their customer routes over peer routes, and how.  For instance, does $NETWORK prefer customers only when the AS path is the same, or all the time no matter what?
> Let's leave out corner cases - e.g. If a customer asks you, via communities or otherwise, to do something different.  This is a poll of default, vanilla configurations.
> Please send them to me, or the list, with this subject line.  I shall compile the results and post them somewhere public.  If you cannot speak for your company, I will keep your name private.

The NTT network has a well documented local-pref policy that shows what is done.

You can review it on the website, including showing that the default local-preference is 120.

Having worked for small players that peered with other partners/networks in the past, not following a model of customer -> peer -> transit order of preference, you can create situations where someone unexpectedly is creating a traffic black hole.

It's not saying you can't build a better model, but this is fairly straightforward and provides expected results.  Your customer routes will always be propagated to your peers.  Having communities to allow the customer to change how their routes are propagated is valuable so they can 'choose their own adventure'.  If someone wants to not announce to another provider, that is their "fault" when traffic breaks.

- Jared

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