Each address family configuration level allows the user to access commands that apply to that particular address family only.
To define IPv4 or IPv6 address families of a VRF, enter the following command.
device(config)# vrf VPN1 device(config-vrf-vpn1)# address-family ipv4 unicast device(config-vrf-vpn1-ipv4)# exit-address-family device(config-vrf-vpn1)# exit-vrf