Error in assignments....?
Stephen J. Wilcox
steve at opaltelecom.co.uk
Tue Jun 11 15:01:35 UTC 2002
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.
>
>
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