Concepts And Terms - HP 6125G Configuration Manual

Figure 57 Application scenario of one-to-two and two-to-two VLAN mapping
Site 1 and Site 2 are in VLAN 2 and VLAN 3, respectively. The VLAN assigned for VPN A is VLAN 10
in the SP 1 network and VLAN 20 in the SP 2 network.
If Site 1 sends a packet to Site 2, the packet is processed on the way to its destination using the following
workflow:
When the packet tagged with VLAN 2 arrives at the edge of network SP 1, PE 1 tags the packet
1.
with outer VLAN 10 by using one-to-two VLAN mapping.
When the double-tagged packet enters the SP 2 network, PE 3 replaces the outer VLAN tag (VLAN
2.
10) with VLAN 20. Because the packet is destined for Site 2 in VLAN 3, PE 3 also replaces the
inner tag (VLAN 2) of the packet with VLAN 3. This process is two-to-two VLAN mapping.
When PE4 receives the packet with the new VLAN tag pair, it removes the outer VLAN tag and
3.
forwards the packet to VLAN 3.
You can use QinQ to implement one-to-two VLAN mapping. For more information about QinQ, see
"Configuring

Concepts and terms

Figure 58 shows a simplified network to help explain the concepts and terms that you might encounter
when you work with VLAN mapping.
Figure 58 Basic concepts of VLAN mapping
QinQ."
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SP
Network-side port
Customer-side port
Uplink traffic
Downlink traffic