H3C Technologies H3C S12500 Series Switches - Manual (Page 207)

194
VLAN termination configuration task list
Task Remarks
Configuring QinQ
termination
Configuring unambiguous QinQ termination
Use at least one method.
Configuring ambiguous QinQ termination
Enabling a VLAN termination-enabled interface to transmit broadcast and
multicast packets
Optional.
Configuring the TPID for VLAN-tagged packets Optional.
Configuring QinQ termination
QinQ termination includes both unambiguous and ambiguous QinQ termination. Unambiguous QinQ
termination allows you to specify only one VLAN ID to be added to packets as the inner VLAN tag.
Ambiguous QinQ termination allows you to specify a range of VLAN IDs, in which a VLAN can be
added to packets as the inner VLAN tag.
QinQ termination enables a VLAN interface to terminate packets whose outermost VLAN tag matches
the VLAN interface number, and to prohibit any other VLAN-tagged packets from passing through.
When QinQ termination is configured, the interface uses the following procedures to process packets:
• When the interface receives a packet, it removes the outermost two layers of VLAN tags of the
packet.
• When the interface sends out a packet, it tags the packet with two layers of VLAN IDs. The outer
VLAN ID is the VLAN interface number. The inner VLAN ID is determined based on the packet
types.
• The interface determines the inner VLAN ID by using the following rules:
{
For a DHCP relay packet, the interface searches the DHCP relay agent bindings to obtain the
inner VLAN ID.
{
For an IPv4 or MPLS packet, the interface searches the ARP table with a specified destination IP
address to obtain the inner VLAN ID.
• If the obtained VLAN ID matches the inner VLAN ID specified in the QinQ termination, the interface
adds the matched inner VLAN tag to the packet.
IMPORTANT:
To obtain the correct VLAN ID, make sure the Layer 2 physical interface to which the VLAN interface is
bound maintains the most recent ARP entries. To do that, execute the reset arp interface command in user
view on the Layer 2 physical interface when the QinQ termination configuration on the VLAN interface is
changed. For more information about this command, see
Layer 3—IP Services Command Reference.
Configuring unambiguous QinQ termination
Step Command Remarks
1. Enter system view. system-view N/A