BGP Confederation question.

From: Matthew Kinnear (matt.kinnear@xxxxxxxxxxx)
Date: Wed May 17 2000 - 14:36:15 GMT-3

Next message: Voltaire Sison: "Trade - Cisco Coursewares"
Previous message: Vijay Venkatesh: "Re: Back to back cables"
Next in thread: Brian Edwards: "RE: BGP Confederation question."
Maybe reply: Brian Edwards: "RE: BGP Confederation question."
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] [ attachment ]

Im currently practicing BGP and am working from Halabi book. The config
examples he has, (p 427) seem to show that you need the confederation id
line only , or the conf id and the conf peer your directly peered with. Im
understanding this to mean that in the example mentioned below, the routers
in AS50 and 70 would not
need to mention each others AS in their own bgp confederation peer
statement......BUT, If I check the same detail in Halabis cse
studies/tutorial, it appears that you need all as's in the confederation
documented in each routers confederation-peer statement.

Im hoping its the latter as this seems more logical....

Matt

-----Original Message-----
From: Brian Edwards [mailto:bedwards@juniper.net]
Sent: 17 May 2000 00:31
To: 'Muthu Mohanasundaram'
Cc: 'ccielab@groupstudy.com'
Subject: RE: BGP Confederation question.

>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.