[48657] in North American Network Operators' Group
Re: Error in assignments....?
daemon@ATHENA.MIT.EDU (Stephen J. Wilcox)
Tue Jun 11 11:02:18 2002
Date: Tue, 11 Jun 2002 16:01:35 +0100 (BST)
From: "Stephen J. Wilcox" <steve@opaltelecom.co.uk>
To: Sabri Berisha <sabri@cluecentral.net>
Cc: Kurt Erik Lindqvist <kurtis@kurtis.pp.se>,
"nanog@nanog.org" <nanog@nanog.org>
In-Reply-To: <20020611150322.J95280-100000@doos.cluecentral.net>
Errors-To: owner-nanog-outgoing@merit.edu
Ugh, this is why ASN's exist and is why ppl have been posting about
inconsistent BGP announcements of late
If you originate the same block from 2 ASNs then you no longer have a
single administrative area and need a 3rd ASN as per the RFC.
Steve
On Tue, 11 Jun 2002, Sabri Berisha wrote:
>
> On Tue, 11 Jun 2002, Kurt Erik Lindqvist wrote:
>
> > > A route is something different then an IP assignment/allocation. There can
> > > be multipe routes and multiple originating AS's for a netblock. The
> > > netblock you are referring to is not globally visible btw.
>
> > Ok, my fault. I ment to say route object. However, I fail to see why (if)
> > you would like to allow the same route to source from muliple AS:es....
>
> Why not?
>
> Suppose company A has a PA allocation 10.21.0.0/20. Company A gets a T1
> from Carrier B. Carrier B announces 10.21.0.0/20 with their AS65531 and
> statically route the /20 to company A. If Company A wants to be redundant
> and gets another T1 from Carrier C, Carrier C will announce 10.21.0.0/20
> with their AS65532 and statically route 10.21.0.0/20 to Company A.
>
> I see no problem in this. If Carrier B screws up, the traffic will still
> flow through Carrier C. If Carrier B screws up in such a way that they
> still announce the netspace, Carrier C can announce 2 /21's instead of 1
> /20 so it will still work.
>
>
