3Com WX3000 Series Operation Manual page 610

To make the packets from the servers be transmitted to the clients in the same way, you need to
configure the selective QinQ feature on GigabitEthernet 1/0/12 and GigabitEthernet 1/0/13. The
configuration on Switch B is similar to that on Switch A and is thus omitted.
The port configuration on Switch B is only an example for a specific network requirement. The key
to this example is to enable the ports to receive and forward packets of specific VLANs. So you can
also configure the ports as access or trunk ports. Refer to Port Basic Configuration for details.
A selective QinQ-enabled device tags a user packet with an outer VLAN tag regardless of the
VLAN tag of the user packet, so there is no need to configure user VLANs on the device.
Make sure the packets of the default VLAN of a selective QinQ-enabled port are permitted on both
the local port and the port connecting to the public network.
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