From: Toh Soon, Lim (tohsoon28@gmail.com)
Date: Fri Aug 24 2007 - 11:40:30 ART
Hi nicky noname,
I'm sorry I don't fully understand what you said.
Anyway looking at your config and based on my understanding, R1 will install
150.12.66.0/24 into its BGP table and tag it with community of no-export. R1
will not advertise it to BB1. You don't even need the command "neighbor BB1
send-community".
Over at R2, you can do "sh ip b com no-ex". You should see the
150.12.66.0/24 route. R2 will honor the no-export community by not
advertising it to BB2. Again, you don't need the command "neighbor BB2
send-community".
Anyone any comments? Do correct me if I'm wrong. I have not labbed this
scenario to confirm.
Thank you.
B.Rgds,
Lim TS
On 8/24/07, nicky noname <cisco2study@gmail.com> wrote:
>
> Hello,
>
> I would very much appreciate some clarification.
>
> I have two routers in AS 2 that have two ebgp connections to backbone 1
> and
> 2 ( one each) in AS 54.
>
> We are to advertise network 150.12.66.0 mask 255.255.255.0 on one router 1
> in AS2.
>
> We do not want this network to be advertised past AS54.
>
> You can send the community attribute no-export to the backbones from R1
> and
> R2, via a route-map matching the network and setting the community and
> then
> sending the route-map to AS54.
>
> The questions is, can we not also, attach the community of no-export,
> direct
> to the network advertisement in BGP on R1, and then send the community
> also
> to R2 and to both Backbone 1 and 2, without specifically pushing a
> route-map
> out to the backbones ( just sending the community attribute) ?
>
> I have attached the later example...it would appear that the prefix will
> not
> leave the local AS?
>
>
>
>
>
> #################################
> R1
>
> router bgp 2
> no synchronization
> bgp router-id xxxx
> bgp log-neighbor-changes
> neighbor R2 remote-as 2
> neighbor R2 send-community
> neighbor BB1 remote-as 54
> neighbor BB1 send-community
> network 150.12.66.0 mask 255.255.255.0 route-map no-export
> no auto-summary
> !
> route-map no-export permit 10
> set community no-export
> !
> ##########################
> R2
>
>
> router bgp 2
> no synchronization
> bgp router-id xxxx
> bgp log-neighbor-changes
> neighbor R1 remote-as 2
> neighbor BB2 remote-as 54
> neighbor BB2 send-community
>
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