If the VLAN ID of the packet is within the range of C-VLANs, the VLAN tag is replaced according to the configuration. If the VLAN ID of the packet is out of the range of C-VLAN IDs or the packet does not carry any tag, the packet is processed as follows:

If qinq vlan-translation miss-drop is used, the packet is discarded directly.

If the qinq vlan-translation miss-drop command is not used on the interface but the default VLAN ID is used, packets are tagged with the default VLAN ID before being forwarded.

NOTE:
In V100R002 and later versions, the implementation of VLAN mapping will be changed as follows: When an interface configured with VLAN mapping received a packet with the C-VLAN ID out of the specified range, the interface transparently transmits the packet through the normal forwarding version if the interface is added to the VLAN of the packet.