Help with proper BGP community configuration.

[ajkelsey78]

I'm learning BGP by reading "BGP for Cisco Networks". It involves hands-on setup of a network. I have currently gotten stuck successfully setting up a community. I am not getting the results shown in the book.

The topology in the book has several AS. Below is the AS that I am configuring the community in.

The community was configured on R4 and I am sending that information to R5. Below is what the book shows is the output. The red arrow marks the line that does not appear for me in my setup.

Below is my output.

For brevity, here are the BGP configuration from R4 and R5. I am happy to provide any additional information.

R4

R5

[Flavio Miranda]

@ajkelsey78 

 Can I see the whole configuration for R4 and R5 ?

[ajkelsey78]

See the attached files.

[Flavio Miranda]

Hi @ajkelsey78 

Check on the guide you are following, The community syntax seems to be wrong.

route-map SET-NEXT-HOP permit 10
match ip address 101
set community 13107500
set ip next-hop peer-address

[ajkelsey78]

For some reason it displays the 32 bit version of the ASNs. You can change that setting with "ip bgp-community new-format" so it shows it as AA:NN. This is with the display change:

[Flavio Miranda]

That´s correct.

Are you seeing the neighboard for BGP and receive router from the neighboards?

[MHM Cisco World]

You only need send-community with each of neighbor in bgp.

That it

MHM

[ajkelsey78]

I'm not sure I understand exactly what you are saying. Upon closer inspection, it looks like I did not assign the neighbors to the peer-group. I think that may resolve it. I will give that a shot and see.

[Flavio Miranda · Accepted solution]

You may missed the command

 neighbor 172.17.5.1 peer-group AS200-PEERGROUP

[ajkelsey78]

This was it. Thanks everyone for getting me on track.

[MHM Cisco World]

You have two peers and you use send-community with irh peer-group not with neighbor.

That why your issue solve when  you use peer-group for neighbor. 

The answer is send-community missing

And for community number 

Use 

Bgp new-format <<- command 

MHM

[Giuseppe Larosa]

Hello @

ajkelsey78

Preview

ip bgp community new format is needed to have BGP community attribute seen as ASN:<value>

BGP standard communities are 32 bits integeers;

as   a final note in "legacy" MPLS L3 VPNs I hawe need wnd communites """both""