Two-To-Two Vlan Mapping; Basic Concepts Of Vlan Mapping - HP 4800G Series Configuration Manual

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Two-to-Two VLAN Mapping

Figure 1-2 Scenario for two-to-two VLAN mapping

Two-to-two VLAN mapping are mainly applied in networking environments as shown in

1-2, two VPN 1 users located in different regions communicate with each other across two

service provider (SP) networks: SP 1 and SP 2.

Assuming that the VPN 1 user using VLAN 10 sends a packet to the VPN 1 user using VLAN 30, the

following describes how this packet is processed on its way to the destination:

When the packet tagged with VLAN 10 arrives at the edge of the SP 1 network, Device A tags the

packet with VLAN 100, the VLAN ID assigned to the VPN 1 user in SP 1 by using QinQ or Selective

QinQ. The packet thus becomes double-tagged.

When the double-tagged packet enters the SP 2 network, Device C replaces the outer VLAN tag

(VLAN 100) with VLAN 200, the VLAN ID assigned by SP 2 to the VPN 1 user. For the packet to

reach the VPN 1 user in VLAN 30, Device C replaces the inner tag (VLAN 10) of the packet with

VLAN 30. This double-tag to double-tag replacement is called two-to-two VLAN mapping.

For more information about QinQ and Selective QinQ, refer to QinQ Configuration in the Access

Before you configure VLAN mappings, be aware of the following concepts, which will be used

throughout this document.

Uplink traffic: Traffic transmitted from a home user network to a distribution network or from a user

network to an SP network.

Downlink traffic: Traffic transmitted from a distribution network to a home user network or from an

SP network to a user network.

Uplink port: A port transmitting uplink traffic and receiving downlink traffic.

Downlink port: A port transmitting downlink traffic and receiving uplink traffic.

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