From: dwhitley@xxxxxxxxx
Date: Thu Feb 01 2001 - 18:28:31 GMT-3
I was going to suggest a similar option using distribute list. Don't
advertise to other AS's any other AS's routes.
-----Original Message-----
From: Andrew Short [mailto:ashort@wingedwheel.net]
Sent: Thursday, February 01, 2001 4:33 PM
To: Mike S. Lee
Cc: CCIE Study Group
Subject: Re: Non-transient AS's in BGP
Someone is GOING to correct me if I am wrong....but I have an untested
suggestion:
1. Add the "no-export" community to ALL eBGP routes coming into your AS.
2. Modify the peering relationship with ALL your iBGP peers so that the
community will be passed on. By default sending the community is turned
off.
router bgp 1
neighbor 2.3.4.5 remote-as 1
neighbor 2.3.4.5 send-community
neighbor 1.2.3.4 remote-as 2
neighbor 1.2.3.4 route-map CommSet in
route map CommSet
set community no-export
Then NO routes LEARNED from eBGP sources will be advertised OUTSIDE the
AS because they are tagged with the no-export attribute. They will,
however, be propagated within the AS, since sending the route to an
internal neighbor isn't "exporting" it.
Since incoming routes are not re-advertised outside the AS, you will
not have a transit AS.
On Thu, 1 Feb 2001, Mike S. Lee wrote:
> Can any one please explain how to make an AS non-transient. I can do this
> with an AS-Path ( ^$) but how would this be accomplished without using an
> AS-Path filter. I have exhausted Halabi and just need to be pushed in the
> right direction. Thanks for any help you can provide.
>
> Mike Lee
> CCNP+LATM+Security+Voice Access/CCDP
> NNCSE/NNCDE
> Cisco Systems, Inc.
> 12515 Research Blvd., Bldg. 04
> Austin, TX 78759-2200
>
> DSL Customer Support Engineering
> mikele@cisco.com
> (512)378-1331 ofc
> Text Page: mikele@epage.cisco.com
> Mike Lee
> CCNP+LATM+Security+Voice Access/CCDP
> NNCSE/NNCDE
> Cisco Systems, Inc.
> 12515 Research Blvd., Bldg. 04
> Austin, TX 78759-2200
>
> DSL Customer Support Engineering
> mikele@cisco.com
> (512)378-1331 ofc
> Text Page: mikele@epage.cisco.com
>
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