Qinq; Introduction; Figure 2-6 Principles Of Basic Qinq - Raisecom ISCOM2600G-HI (A) Series Configuration Manual

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ISCOM2600G-HI (A) Series Configuration Guide

2.4 QinQ

2.4.1 Introduction

QinQ (also known as Stacked VLAN or Double VLAN) technique is an extension to 802.1Q
defined in IEEE 802.1ad standard.
Basic QinQ
Basic QinQ is a simple Layer 2 VPN tunnel technique, which encapsulates outer VLAN Tag
for user private network packets at carrier access end, then the packet with double VLAN Tag
traverse backbone network (public network) of the carrier. On the public network, packets are
transmitted according to outer VLAN Tag (namely, the public network VLAN Tag), the user
private network VALN Tag is transmitted as data in packets.

Figure 2-6 Principles of basic QinQ

Typical networking of basic QinQ is shown as Figure 2-6; the ISCOM2600G-HI series switch
is the PE.
Packets are transmitted from the user device to the PE, and the VLAN ID of packet tag is 100.
Packet will be added with outer tag with VLAN 1000 when traversing from the PE device at
the network side interface to the carrier network.
Packets with the VLAN 1000 outer Tag are transmitted to PE device on the other side by the
carrier, and then the PE will remove the outer tag VLAN 1000 and send packets to the user
device. Now the packets return to carrying only one tag VLAN 100.
This technique can save public network VLAN ID resources. You can plan private network
VLAN ID to avoid conflict with public network VLAN ID.
Selective QinQ
Selective QinQ is an enhancement to basic QinQ, which classifies flow according to user data
features, then encapsulates different types flow into different outer VLAN Tags. This
technique is implemented through combination of interface and VLAN. Selective QinQ can
perform different actions on different VLAN Tags received by one interface and add different
outer VLAN IDs for different inner VLAN IDs. According to configured mapping rules for
inner and outer Tags, you can encapsulate different outer Tags for different inner tagged
packets.
Selective QinQ makes structure of the carrier network more flexible. You can classify
different terminal users on the access device interface by VLAN Tag and then, encapsulate
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