190
When a tagged Ethernet frame from CE 1 arrives at PE 1, the PE tags the frame with SVLAN 3. The
double-tagged Ethernet frame travels over the service provider network until it arrives at PE 2. PE 2
removes the SVLAN tag of the frame, and then sends the frame to CE 4.
Figure 57 Typical QinQ application scenario
QinQ implementations
QinQ is enabled on a per-port basis. The link type of a QinQ-enabled port can be access, hybrid, or
trunk. The QinQ tagging behaviors are the same across these types of ports.
A QinQ-enabled port tags all incoming frames (tagged or untagged) with the PVID tag.
•
If an incoming frame already has one tag, it becomes a double-tagged frame.
•
If the frame does not have any 802.1Q tags, it becomes a frame tagged with the PVID.
QinQ provides the most basic VLAN manipulation method to tag all incoming frames (tagged or
untagged) with the PVID tag. To perform advanced VLAN manipulations, use VLAN mapping (see
"
") or QoS policies. For example:
•
To use different SVLANs for different CVLAN tags, use one-to-two VLAN mapping.
•
To replace the SVLAN ID, CVLAN ID, or both IDs for an incoming double-tagged frame, use
two-to-two VLAN mapping.
•
To set the 802.1p priority in SVLAN tags, configure a QoS policy as described in "
."
Protocols and standards
•
IEEE 802.1Q,
IEEE Standard for Local and Metropolitan Area Networks-Virtual Bridged Local
Area Networks
•
IEEE 802.1ad,
IEEE Standard for Local and Metropolitan Area Networks-Virtual Bridged Local
Area Networks-Amendment 4: Provider Bridges
PE 1
Service provider network
Internet
PE 2
VLANs 1 to 20
Customer
network B
CE 3
Customer
network A
VLANs 1 to 10
CE 1
VLANs 1 to 10
Customer
network A
CE 4
VLANs 1 to 20
Customer
network B
CE 2
Data
SVLAN 4 CVLAN B
Data
SVLAN 3 CVLAN A
Data
SVLAN 4 CVLAN B
Data
SVLAN 3 CVLAN A
Data
CVLAN B
Data
CVLAN B
Data
CVLAN A
Data
CVLAN A
Содержание H3C S7500E-X
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