RE: BGP Confederation question.

From: Brian Edwards (bedwards@xxxxxxxxxxx)
Date: Tue May 16 2000 - 20:30:40 GMT-3

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>1. It is required to fully mesh the sub-ASes, that is
>do I have configure EBGP peers between AS50 and AS70
>also ?
>(I have a feeling it is not required, but I wanted to
>confirm.)

No.

>2. If I only need EBGP peering on AS50 with AS60, (and
>not with AS70), then do I have to include the AS
>number 70 in my "bgp confederation peers 60" statement
>on AS50's border router ? That is, the question is, do
>we have to include all the sub-AS numbers in this
>statement or only the sub-AS numbers of the ASes you
>are EBGP peering with?

Yes. The confed peers needs to list all subAS's that you want to describe to
the outside world as your majorAS (aka "bgp confederation identifier"). If
you did not include 70. The AS-path of routes generated in 70 would look
like this on routers external to your AS: "100 70", buy you want it to look
like this "100".

-----Original Message-----
From: Muthu Mohanasundaram [mailto:mmsundar@yahoo.com]
Sent: Tuesday, May 16, 2000 3:51 PM
To: ccielab@groupstudy.com
Subject: BGP Confederation question.

Hi All,

Let's say we have three sub-ASes 50, 60 and 70
connected sequencially like this:

(AS50)---(AS60)---(AS70)

They are part of the BGP confederation 100.

I know that within the subAS, all the BGP routers need
to be fully meshed. Cool.

1. It is required to fully mesh the sub-ASes, that is
do I have configure EBGP peers between AS50 and AS70
also ?
(I have a feeling it is not required, but I wanted to
confirm.)

2. If I only need EBGP peering on AS50 with AS60, (and
not with AS70), then do I have to include the AS
number 70 in my "bgp confederation peers 60" statement
on AS50's border router ? That is, the question is, do
we have to include all the sub-AS numbers in this
statement or only the sub-AS numbers of the ASes you
are EBGP peering with?

Any help would be highly appreciated.