Suppose that we have QinQ traffic that reaches a GigabitEthernet interface of a GSR. (The second VLAN tag has been previously imposed at a dot1q-tunnel interface of some edge switch. Traffic that reaches the GSR has 2 VLAN tags.) We want to deliver this traffic (over an MPLS backbone) to the GigabitEthernet interface of another GSR. What configuration options are there ? Would a configuration like the following (symmetrically configured at both GigabitEthernet interfaces) work and why ?
interface GigabitEthernet s1/s2/s3.x
encapsulation dot1Q x
xconnect <peer-router-id> <vc-id> encapsulation mpls
(x above is supposed to play the role of the outermost/service VLAN tag)
I am wondering whether the command encapsulation dot1q second-dot1q is actually needed or not.
Any answers or documentation or related standards/drafts will be appreciated.