Want a way to convert your BGP configuration to the “new style” BGP configuration command structure without a major overhaul of the config? Most of the time the “new-style” configuration is associated with configurations related to MPLS VPN’s and usually that is correct…but what if you’re an SP that is migrating to an MPLS service base offering …. You need a way to migrate your traditional BGP config to the new-style without having to re-create your BGP config…Then afterwards you can begin to create your address family for vpnv4 exchange and any VRFs you need to define. Let’s look at how you can do this.

router bgp 100
no synchronization
bgp log-neighbor-changes
neighbor 200.200.200.200 remote-as 100
neighbor 200.200.200.200 description BGP Session to R2
neighbor 200.200.200.200 password CCIE6200
neighbor 200.200.200.200 update-source Loopback0
neighbor 200.200.200.200 route-reflector-client
neighbor 200.200.200.200 send-community extended
neighbor 200.200.200.200 send-label
no auto-summary
!
R1#sh ip bgp neighbors
BGP neighbor is 200.200.200.200, remote AS 100, internal link
Description: BGP Session to R2
BGP version 4, remote router ID 200.200.200.200
BGP state = Established, up for 00:25:21
Last read 00:00:21, hold time is 180, keepalive interval is 60 seconds
Neighbor capabilities:

My sample router has a very basic traditional BGP config loaded. We can see that R1 has an established neighbor relationship with R2 at 200.200.200.200….don’t worry about all the other configuration commands there they are simple for the sake of this discussion. Now let’s say you want to start the migration to the new style configuration commands. You can do this by disabling the IPv4 unicast address family as the default for BGP session establishment using the ‘bgp default ipv4-unicast’ configuration command under the traditional BGP routing process. Once you do this, the router automatically create the address-family ipv4 for ipv4 address exchange and it will activate your neighbor session for you. Let’s look at an example:

R1#config t
Enter configuration commands, one per line. End with CNTL/Z.
R1(config)#router bgp 100
R1(config-router)#bgp default ipv4-unicast
R1(config-router)#do sh run | b router bgp
router bgp 100
bgp log-neighbor-changes
neighbor 200.200.200.200 remote-as 100
neighbor 200.200.200.200 description BGP Session to R2
neighbor 200.200.200.200 password CCIE6200
neighbor 200.200.200.200 update-source Loopback0
!
address-family ipv4
neighbor 200.200.200.200 activate
neighbor 200.200.200.200 route-reflector-client
neighbor 200.200.200.200 send-community extended
neighbor 200.200.200.200 send-label
no auto-summary
no synchronization
exit-address-family
!