If the VLAN ID of the packet is within the configured QinQ C-VLAN range, the VLAN tag is added to the packet according to the configuration.

If the VLAN ID of the packet is not within the configured QinQ C-VLAN range or the packet does not carry any tag, the packet is processed as follows:

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