Introduction to BGP Peer Groups

Introduction to BGP Peer Groups

It is very important to understand the concept of the BGP peer groups. So if you able to understand the concept by name as they have a group by which they share same kind of policies and the configurations. Now the question is why we are doing this. 

Sometimes we have a network where we really want to deploy the same kind of the configuration with the same policies and we can achieve in two different ways. One is to configure all the router one by one manually and it is a time consuming task. 

The other way to define the same set of the configurations and the policies is to set up with the peer groups in the BGP. So if there are 4 routers and we want to have these routers with same kind of configurations and the policies we can set all of them in a peer group.

So with the above explained definition hope you guys understand the concept of the peer group. Now we are going to talk about the configuration with the help of the topology. The Topology and the IP used in this article is for demo purposes and has no relevance with any of the live and the enterprise networks.

Fig 1.1- BGP Peer Groups

    Configurations on NDNA_R4

Now as all the routers in the BGP peer groups, it means the above mentioned configurations apply on all the Routers NDNA_R5, NDNA_R6 and NDNA_R7. Make sure you understand that Routers NDNA_R1, NDNA_R2 and NDNA_R3 are on different AS and will not replicate the same configuration.

Now take a different path or a twist, configure a BGP peer group named NDNA_EXT on NDNA_R4 and apply it to routers in AS 100, 200, and 300.

  Configurations on NDNA_R4

Now all the configurations are set on all the routers AS 100, AS 200 and AS 300. In the above configurations, the neighbor remote-as router configuration commands are placed outside of the neighbor peer-group router configuration commands because different external ASs have to be defined. 

⭐ Note: This configuration defines filter list 3, which can be used to override configuration options for incoming updates from the neighbor at IP address