From: Rajeevan Chamackalil (Rajeevan@xxxxxxxxxxxxx)
Date: Tue Oct 03 2000 - 03:17:22 GMT-3
Siddiqui,
R4 is directly connected to R2 in As 300, not through the AS-100.
( I am sorry if diagram is not clear )
So if I configure community attribute at R4 as no-export
pointing to r2, that will affect both r1 and r3. Ie R1 and R3 will not get
aggreagte routes. So I feel, that will not solve our problem. Correct me if
I am wrong.
As per franks sugestion I am looking more into preifx list.
Thanks
Rajeevan
-----Original Message-----
From: Siddiqui, Maqsood
To: 'Frank Jimenez'; Muthu; ccielab@groupstudy.com
Sent: 10/2/00 10:08 PM
Subject: RE: BGP aggregation
aside from filtering, you could also try modifying the community
attribute
of the more specific (or the agg) routes using route-maps applied to
each
neighbor. for example:
neigh x.x.x.x send-community
neigh x.x.x.x route-map SETCOMMUNITY out
route-map SETCOMMUNITY permit 10
set community no-export <---------- do not export to next AS
or
set community no-advertise <------- do not advertise to any peer
however, the routers in your diagram will both receive the more specific
routes; modifying the community attribute will simply prevent others
(either
in the same AS or different AS's) from learning them.
maqsood
-----Original Message-----
From: Frank Jimenez [mailto:franjime@cisco.com]
Sent: Monday, October 02, 2000 11:33 PM
To: Muthu; ccielab@groupstudy.com
Subject: Re: BGP aggregation
Take a look at 'ip prefix-list' - that might lead you off into the right
direction....
Frank Jimenez, CCIE #5738
franjime@cisco.com
At 06:30 PM 10/02/2000 -0600, you wrote:
>Hi team,
>
>I have a scenario like this
>
>
>
>R1(AS-100 )--------------R2(AS-300 )------------------------R3(AS-400)
> .
> .
> .
> .
> .
> R4(500)
>
>
>R1 in AS 100
>R3 in AS 400
>R4 in AS 500
>R2 in AS 300
>
>All these three routers have EBGP peering with R2 which is in AS 300
>R4 is advertising two routes 171.1.2.0 and 171.1.3.0
>The requirement is R1 should see these routes as summarised form ie :
>171.1.0.0
>whereas R3 should see both the routes without summarisation.
>
>
>if we use " bgp aggregate address 171.1.0.0 mask 255.255.0.0
summary-only"
in
>r2, both R1 and R3 get aggregate routes.
>So that is not the correct way. It looks like aggregate address to
specified
>with respect to neighbor. But I am unable to use
>above command to a specific neighbor.
>
>Any help will be greatly appreciated
>
>Thanks
>Muthu
>
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