BGP Dynamic Neighbors (Listen Range)

Background Information

1. Instead of specifying individual neighbors by IP address, you can specify a subnet to allow connections from.
2. This reduces the amount of configuration required to peer up with a bunch of routers.
3. Requires the use of peer groups.

Summary

1. neighbor X peer-group to create a peer group.
2. bgp listen range peer-group to specify the neighbor subnet and bind them to the peer group.
3. bgp listen limit to set a limit on how many dynamic peers can connect.
4. show ip bgp sum to view the listen range.

router bgp 6500

  neighbor PEERS peer-group

  neighbor PEERS remote-as 6500

  neighbor PEERS update-source lo0

  bgp listen range 10.0.0.0/28 peer-group PEERS

  bgp listen limit 10

show ip bgp sum 

  
http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/iproute_bgp/configuration/xe-3sg/irg-xe-3sg-book/irg-dynamic-neighbor.html