[30391] in North American Network Operators' Group

home help back first fref pref prev next nref lref last post

Re: two AS announce the same adress space

daemon@ATHENA.MIT.EDU (Mikael Abrahamsson)
Tue Aug 1 17:33:40 2000

Date: Tue, 1 Aug 2000 23:29:47 +0200 (MEST)
From: Mikael Abrahamsson <swmike@swm.pp.se>
To: nanog@nanog.org
In-Reply-To: <Pine.LNX.4.10.10008011015200.31794-100000@uplift.swm.pp.se>
Message-ID: <Pine.LNX.4.10.10008012326370.31794-100000@uplift.swm.pp.se>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
Errors-To: owner-nanog-outgoing@merit.edu


On Tue, 1 Aug 2000, Mikael Abrahamsson wrote:

> What will break if two different ASes announce the exact same adress
> space?

I have gotten approx 10-12 replies to this privately, and would just like
to say thanks for all the good input.

To summarize:

This is not allowed during to RFC.
It is "best practice" not to do it.
Several people do it and report that it works well.

Some warn that some BGP implementations might drop the announcement.

end summary:

One of the reason to do this is because one would not want to "waste" AS
just because one wants to do a single multihoming. What will happen when
we run out of ASes? As far as I can see 1/4 of the AS space is now
consumed.

-- 
Mikael Abrahamsson    email: swmike@swm.pp.se



home help back first fref pref prev next nref lref last post