Anyone notice strange announcements for

Tim Franklin tim at
Wed Jan 14 10:50:23 UTC 2009

On Tue, January 13, 2009 8:57 pm, Joe Abley wrote:

> The fact that I choose to stick 701 in an AS_PATH attribute on a
> prefix I advertise in order to stop that prefix from propagating into
> 701 is entirely my own business, and it's a practice which, although
> apparently not commonplace, has been a well-known part of the IDTE
> toolbox for many years.

This does seem to be an interesting question.

I'm AS X, I have no contractual relationship with AS Y, or indeed any
informal peering relationship with them.  All of my connectivity with AS Y
is via at least one other AS.

For whatever reason, technical, political, or pure whim, I don't want AS Y
to receive any of my announcements.

What's the correct tool to do this?

Other than AS-PATH, I can't see a reliable way to do this currently.  Lots
of my peers or transits may have communities I can set to request that
they don't announce my routes in particular regions, at particular peering
points etc, but they almost certainly don't have one to restrict
announcements to a specific AS.

Do we need a set of well-known communities XXXXX:AS that can be recognised
everywhere as "do not announce to AS"?


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