H3C S7500 Series Ethernet Switches Operation Manual

Operation Manual – QinQ
H3C S7500 Series Ethernet Switches Chapter 1
QinQ Configuration
1-1
Chapter 1 QinQ Configuration
1.1 QinQ Overview
1.1.1 Introduction to QinQ
The QinQ function enables packets to be transmitted across the operators’ backbone
networks with VLAN tags of private networks encapsulated in those of public networks.
In public networks, packets of this type are transmitted by their outer VLAN tags (that is,
the VLAN tags of public networks). And those of private networks which are
encapsulated in the VLAN tags of public networks are shielded.
Figure 1-1 illustrates the structure of a single-tagged packet.
Destination MAC address
0
31
Data
Source MAC address
15
VLAN Tag
Figure 1-1 Structure of a single-tagged packet
Figure 1-2 illustrates the structure of a double-tagged packet.
Destination MAC address
0
31
Data
Source MAC address
15
Inner VLAN Tag
Outer VLAN Tag
Figure 1-2 Structure of a double-tagged packet
Compared with MPLS-based Layer 2 VPN, QinQ has the following features:
z It provides simpler Layer 2 VPN tunnels.
z QinQ can be implemented through static configurations only, without the support
of signaling protocols.
The QinQ function provides you with the following benefits:
z Saves public network VLAN ID resources.