Qinq Configuration - 3Com 7757 Configuration Manual

160 C 19: Q Q C
HAPTER IN
Implementation of QinQ
Inner-to-Outer Tag
Priority Mapping

QinQ Configuration

Configuration
Prerequisites
Configuration Procedure
ONFIGURATION
Saves public network VLAN ID resource.
■
You can have VLAN IDs of your own, which is independent of public network
■
VLAN IDs.
Provides simple Layer 2 VPN solutions for small-sized MANs or intranets.
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QinQ can be implemented by enabling the QinQ function on ports.
With the QinQ function enabled for a port, the switch will tag a received packet
with the default VLAN tag of the receiving port no matter whether or not the
packet already carries a VLAN tag, and the switch will learn the source MAC
address of the packet into the MAC address table of the default VLAN. If the
packet already carries a VLAN tag, the packet becomes a dual-tagged packet.
Otherwise, the packet becomes a packet carrying the default VLAN tag of the
port.
As shown in Figure 45, IEEE 802.1Q defines the structure of tagged packets in
Ethernet frames:
Figure 45 The structure of tagged packets of Ethernet frames
6bytes
DA
The user priority field is the 802.1p priority of the tag. This 3-bit field is in the
range of 0 to 7. Through configuring inner-to-outer tag priority mapping for a
QinQ-enabled port, you can assign different priority for the outer tag of a packet
according to its inner tag priority.
Refer to "Setting Port Priority" on page 666 for the detailed configurations about
priority mapping.
Make sure that Voice VLAN is not enabled for the port where QinQ is to be
enabled. The QinQ feature is mutually exclusive with the Voice VLAN feature.
n
BPDU tunnel is a specific application of the QinQ feature. The BPDU tunnel feature
uses the vlan-vpn tunnel command to transmit the customers' MSTP packets
transparently through the service provider's network. Refer to "BPDU Tunnel
Configuration" on page 272.
Table 98 Configure QinQ
Operation
Enter system view
6bytes 4bytes 2bytes
SA VLAN Tag Etype
2bytes 3bits 1bit
TPID User Priority CFI
Command
system-view
46 1500bytes 4bytes
DATA FCS
12bits
VLAN ID
Description
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