From: Dayong Gan (dygan@xxxxxxxxx)
Date: Tue Oct 03 2000 - 10:48:27 GMT-3
configure aggregate-address 171.1.0.0 255.255.0.0 on
R2 (no summary-only!!!). R2 will have the aggregate
and the specific routes. then filter the route out to
r1 and r3 seperately.
neighbor R1 distribute-list 100 out
neighbor R3 distribute-list 110 out
access-list 100 per ip 171.1.0.0 0.0.255.255 host
255.255.0.0
access-list 110 per ip 171.1.0.0 0.0.255.255 host
255.255.255.0
Hope this helps
Dayong
--- Rajeevan Chamackalil <Rajeevan@euclidnet.com>
wrote:
> 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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