3com 8807 User Guide
76
Q
IN
Q C
ONFIGURATION
QinQ Overview
Introduction to QinQ
QinQ refers to the technology that enables packets to be transmitted across the
operators’ backbone networks with VLAN tags of private networks nested 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 nested in the VLAN tags of public networks, remain
intact.
operators’ backbone networks with VLAN tags of private networks nested 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 nested in the VLAN tags of public networks, remain
intact.
Figure 196 describes the structure of the packets with single VLAN tags.
Figure 196 Structure of packets with private network VLAN tags
Figure 197 describes the structure of the packets with nested VLAN tags.
Figure 197 Structure of packets with nested VLAN tags
Compared with MPLS-based L2VPN, QinQ has the following features:
■
Layer 2 VPN tunnels that are simpler.
■
QinQ can be implemented without the support of signaling protocols. You can
enable QinQ by static configuring.
enable QinQ by static configuring.
As QinQ is implemented through trunk port defined in 802.1Q, all devices along
tunnels with QinQ employed must be 802.1Q-enabled. Therefore, QinQ is suitable
for small-sized metropolitan area networks (MANs) or intranets with Layer 3
switches operate as the core layer devices.
tunnels with QinQ employed must be 802.1Q-enabled. Therefore, QinQ is suitable
for small-sized metropolitan area networks (MANs) or intranets with Layer 3
switches operate as the core layer devices.
QinQ provides you with the following benefits:
■
Saves public network VLAN IDs.
■
You can have VLAN IDs of your own, which do not conflict with public network
VLAN IDs.
VLAN IDs.
■
Provide simple Layer 2 VPN solutions for small-sized MANs or intranets.
DA
(6B)
SA
(6B)
ETYPE(8100)
(2B)
Nested VLAN TAG
(2B)
ETYPE
(2B)
DATA
User VLAN TAG
(2B)
ETYPE
(2B)
DA
(6B)
SA
(6B)
(2B)
Nested VLAN TAG
(2B)
ETYPE
(2B)
DATA
(0~1500B)
FCS
(4B)
(2B)
(2B)
DA
(6B)
SA
(6B)
ETYPE(8100)
(2B)
Nested VLAN TAG
(2B)
ETYPE
(2B)
DATA
(2B)
ETYPE
(2B)
DA
(6B)
SA
(6B)
(2B)
Nested VLAN TAG
(2B)
ETYPE
(2B)
DATA
(0~1500B)
FCS
(4B)
(2B)
(2B)
DA
(6B)
SA
(6B)
ETYPE(8100)
(2B)
Nested VLAN TAG
(2B)
ETYPE
(2B)
DATA
User VLAN TAG
(2B)
ETYPE
(2B)
DA
(6B)
SA
(6B)
(2B)
Nested VLAN TAG
(2B)
ETYPE
(2B)
DATA
(0~1500B)
FCS
(4B)
(2B)
(2B)
DA
(6B)
SA
(6B)
ETYPE(8100)
(2B)
Nested VLAN TAG
(2B)
ETYPE
(2B)
DATA
(2B)
ETYPE
(2B)
DA
(6B)
SA
(6B)
(2B)
Nested VLAN TAG
(2B)
ETYPE
(2B)
DATA
(0~1500B)
FCS
(4B)
(2B)
(2B)