router bgp 1
bgp router-id 1.0.0.133
vrf CUST1
rd 100:1
address-family ipv4 unicast
!
address-family ipv6 unicast
!
neighbor 100.96.100.1
remote-as 200
address-family ipv4 unicast
route-policy PASS in
route-policy PASS out
!
address-family ipv6 unicast
route-policy PASS in
route-policy PASS out
Cisco IOS XE:
router bgp 200
!
address-family ipv4 vrf CUST1
bgp router-id 100.96.100.1
neighbor 100.96.100.2 remote-as 1
neighbor 100.96.100.2 update-source GigabitEthernet0/1.100
neighbor 100.96.100.2 activate
exit-address-family
!
#####it will not establish as XE has only IPV4 and missing IPV6 address family.#####