From: Howard C. Berkowitz (hcb@xxxxxxxxxxxx)
Date: Sun Mar 24 2002 - 11:50:13 GMT-3
First, let me clarify a bit of terminology. BGP doesn't have areas.
It has autonomous systems. An AS can contain confederation AS and
route reflectors.
It is the IGP cooperating with BGP that may have areas.
At 12:12 AM -0500 3/24/02, Mannan Venkatesan wrote:
>Something else came on my mind, but I need to check it. How about tagging
>the routes on the edge bgp routers and then on the other end deny those
>tagged routes to outside world???
>
>Mannan
You certainly could, and this is probably something to consider in
preparing for the artificial environment of the lab. Nevertheless,
the NO-EXPORT community is the way BGP protocol designers intended to
do this in a non-confederation environment. Even with confederations,
there are communities intended to keep routes inside single
confederation AS, or within the set of confederation AS.
While this is a concept beyond the scope of the exam, do be aware
there are two meanings of transit in BGP. Here, we are talking about
the behavior of a single AS, in that it will carry traffic from one
AS to another. There are also economic meanings. For the latter,
see, for example,
http://www.ietf.org/internet-drafts/draft-huston-nopeer-00.txt
>
>----- Original Message -----
>From: "Ouellette, Tim" <tim.ouellette@eds.com>
>To: "'Carl Phelan'" <carlphelan@hotmail.com>
>Cc: <ccielab@groupstudy.com>
>Sent: Saturday, March 23, 2002 7:39 PM
>Subject: RE: BGP - Transit Area
>
>
>> Try setting a community of no-export on routes incoming from both of your
>> ebgp peers. Obviously if your concerned about being non-transit then you
>> have multiple connections to the "outside world" with multiple providers.
>>
>> If anyone else has other ways please respond!
>>
>> Tim
>>
>>
>> -----Original Message-----
>> From: Carl Phelan [mailto:carlphelan@hotmail.com]
>> Sent: Saturday, March 23, 2002 12:00 PM
>> To: ccielab@groupstudy.com
>> Subject: BGP - Transit Area
>>
>>
>> Hi All,
>>
>> I am practising doing normal tasks in different ways - as expected for
>> the lab. In BGP, what is the simplest way to make an area a non-transit
>> area without using an AS path filter?
>>
>> Many thanks for any advice.
>>
> > Carl
-- "What Problem are you trying to solve?" ***send Cisco questions to the list, so all can benefit -- not directly to me*** ******************************************************************************* * Howard C. Berkowitz hcb@gettcomm.com Chief Technology Officer, GettLab/Gett Communications http://www.gettlabs.com Technical Director, CertificationZone.com http://www.certificationzone.com "retired" Certified Cisco Systems Instructor (CID) #93005
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