Inter-AS option C is fully setup and working. Add L2VPN support. CSR1 should have connectivity on VRF L2A and VRF L2B. An OSPF adjacency will form once connectivity is established.
Use EVPN E-LAN
BGP l2vpn/evpn is already enabled
Use Q-in-Q 3999/168 on R6 to R1, and Q-in-Q 3998/268 on R8 to R1
Answer
#R6
int gi2
service instance 100 eth
encapsulation dot1Q 3999 second-dot1q 168
rewrite ingress tag pop 2 symm
exit
exit
!
l2vpn evpn
replication-type ingress
!
l2vpn evpn instance 100 vlan-based
route-target both 100:100
no auto-route-target
!
bridge-domain 100
member gi2 service-instance 100
member evpn 100
#R8
int gi2
service instance 100 eth
encapsulation dot1Q 3998 second-dot1q 268
rewrite ingress tag pop 2 symm
exit
exit
!
l2vpn evpn
replication-type ingress
!
l2vpn evpn instance 100 vlan-based
route-target both 100:100
no auto-route-target
!
bridge-domain 100
member gi2 service-instance 100
member evpn 100
#R7
router bgp 65001
address-family l2vpn evpn
neighbor 10.0.0.14 activate
neighbor 10.0.0.14 next-hop-unchanged
#XR14
router bgp 65002
neighbor 10.0.0.7
address-family l2vpn evpn
route-policy PASS in
route-policy PASS out
next-hop-unchanged
Explanation
L2VPN services with inter-AS option C is quite simple. This is because the loopbacks are directly distributed between the ASs, so it gives the feel of an inter-AS service.
The only complexity is dealing with route-targets with EVPN. By default, the RT is auto-generated as <ASN>:<EVI>. The local PE will not import the remote PE’s EVPN routes. You can either manually import the remote AS’s RT, or manually specify the same RT on both ASs.
#R6, R8
l2vpn evpn instance 100 vlan-based
route-target both 100:100
no auto-route-target
Also, the route reflectors must enable the l2vpn/evpn address-family. Again, make sure to use next-hop-unchanged to leave the nexthop of the local PE intact when advertising the route to the eBGP RR neighbor.
