197
•
IEEE 802.1ad,
IEEE Standard for Local and Metropolitan Area Networks-Virtual Bridged Local Area
Networks-Amendment 4: Provider Bridges
Restrictions and guidelines
When you configure QinQ, follow these restrictions and guidelines:
•
EVB and QinQ are mutually exclusive. Do not enable both features on a port.
•
Before you configure QinQ on a port, remove existing VLAN mapping configuration on it. After you
enable QinQ on the port, you can configure all VLAN mapping types except two-to-two VLAN
mapping. If QinQ and a VLAN mapping conflict, the VLAN mapping takes effect.
•
The inner 802.1Q tag of QinQ frames is treated as part of payload. For correct transmission of
QinQ frames, H3C recommends that you set the MTU to a minimum of 1504 bytes for each port on
the forwarding path of QinQ frames. This value is the sum of the default Ethernet interface MTU
(1500 bytes) and a VLAN tag's size (4 bytes).
Enabling QinQ
Enable QinQ on customer-side ports of PEs. A QinQ-enabled port tags an incoming frame with its PVID.
To enable QinQ:
Step
Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter Layer 2 Ethernet
interface view or Layer 2
aggregate interface view.
interface
interface-type
interface-number
N/A
3.
Enable QinQ.
qinq enable
By default, QinQ is disabled.
Configuring transparent transmission for VLANs
You can exclude traffic of a VLAN (for example, the management VLAN) from the QinQ tagging action
on a customer-side port. This VLAN is called a transparent VLAN.
To ensure successful transmissions for a transparent VLAN, follow these configuration guidelines:
•
Set the link type of the port to trunk or hybrid, and assign the port to the transparent VLAN.
•
Do not configure any other VLAN manipulation actions for the transparent VLAN on the port.
•
Make sure all ports on the traffic path permit the transparent VLAN to pass through.
To enable transparent transmission for a list of VLANs:
Step
Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter Layer 2 Ethernet
interface view or Layer 2
aggregate interface view.
interface
interface-type
interface-number
N/A
