Cisco BGP Dynamic Neighbor
After an IPv4 subnet range is configured for a iBGP peer group and a TCP session is initiated
by another router which has an IP address in the IPv4 subnet range, a new BGP neighbor will be dynamically established as a member of that group.
Here is the example:
router bgp 1
bgp listen range 10.1.1.0/24 peer-group SPOKES
bgp listen limit 1000
neighbor SPOKES peer-group
neighbor SPOKES remote-as 1
neighbor SPOKES transport connection-mode passive
neighbor SPOKES route-reflector-client
HUB#show ip bgp sum
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
*10.1.1.3 4 1 70069 70100 160 0 0 5w0d 3
*10.1.1.4 4 1 80416 80459 160 0 0 5w1d 3
* Dynamically created based on a listen range command
Dynamically created neighbors: 2 Subnet ranges: 1
BGP peergroup DMVPN listen range group members:
10.1.1.0/24
Total dynamically created neighbors: 2/(1000 max), Subnet ranges: 1
