Configuring Dot1q termination
Based on the range of outermost VLAN IDs in the VLAN-tagged packets that can be terminated by a subinterface, the following types of Dot1q termination are available:
Ambiguous Dot1q termination—Terminates VLAN-tagged packets whose outermost VLAN IDs are in the specified range. Any other VLAN-tagged packets are not allowed to pass through this subinterface.
When the subinterface receives a packet, it removes the outermost layer of tags from the packet. When the subinterface sends a packet, it tags the packet with a VLAN ID as follows:
For a PPPoE packet, the VLAN ID is obtained by searching the PPPoE session entries.
For a DHCP relay packet, the VLAN ID is obtained by searching the DHCP session entries.
For an IPv4 or MPLS packet, the VLAN ID is obtained by searching the ARP entries.
Unambiguous Dot1q termination—Terminates only VLAN-tagged packets whose outermost VLAN ID matches the specified VLAN ID. Any other VLAN-tagged packets are not allowed to pass through this subinterface.
When the subinterface receives a packet, it removes the outermost VLAN tag of the packet.
When the subinterface sends a packet, it tags the packet with the specified VLAN ID.