BGP Address-family Ipv4 Is Used

 To advertise routes we need to use MP-iBGP and hence to enable this MP-iBGP we need to use
address-family VPNv4. Then by default the neighbors in this family are deactivated by default and hence
we need to use activate command.

once we enable the vpn family the neighbors on the global bgp will deactivated in order to stop that we
need to put the neighbors in address-family ip4 and then activate it. It is mainly used in MPLS VPN environment.

“address-family” command is necessary when the packets go through MPLS backbone.

You need to put two commands to enable MP-BGP session 1) activate 2) send community.