3Com Switch 4500 Family Manual page 860

If XRN fabric is enabled on a device, the selective QinQ policy cannot be configured on any port of the
device.
By default, no selective QinQ policy is configured on a port.
After specifying an outer VLAN tag and enter QinQ view, you need to use the raw-vlan-id inbound
command to specify which VLANs' packets will be encapsulated with the specified outer VLAN tag.
Otherwise, the configuration of the outer VLAN tag is of no use.
Related commands: raw-vlan-id inbound.
Examples
# Specify Ethernet 1/0/1 add VLAN 20 tag as the outer tag to the packets with their inner VLAN IDs
being 2 through 14.
<Sysname> system-view
System View: return to User View with Ctrl+Z.
[Sysname] interface Ethernet 1/0/1
[Sysname-Ethernet1/0/1] vlan-vpn vid 20
[Sysname-Ethernet1/0/1-vid-20] raw-vlan-id inbound 2 to 14
2-4