Huawei quidway s7700 - Page 594

Figure 11-5 Networking of QinQ-based Layer 2 protocol transparent transmission
CE-VLAN 200
ISP Network
PE 1
PE 2
LAN-A
MSTP
LAN-B
MSTP
LAN-B
MSTP
LAN-A
MSTP
CE-VLAN 100
PE-VLAN20:CE-VLAN 100~199
PE-VLAN30:CE-VLAN 200~299
CE-VLAN 200
CE-VLAN 100
BPDU Tunnel
BPDU Tunnel
When a great number of user networks are connected to the backbone network, considerable
VLAN IDs of the ISP are required if packets are transparently transmitted based on VLANs.
In this case, BPDUs can be forwarded in QinQ mode on the backbone network.
As shown in Figure 11-5, QinQ-based Layer 2 protocol transparent transmission is
configured on aggregation interfaces of PEs. Packets from different user networks are
encapsulated in different outer VLAN tags. QinQ-based Layer 2 protocol transparent
transmission is implemented as follows:
1. Configure devices on user networks to send Layer 2 protocol packets with the specified
VLAN IDs to the backbone network.
2. Enable Layer 2 protocol transparent transmission and QinQ on interfaces of the ingress
device on the backbone network.
3. Configure PEs to add different outer VLAN tags (public VLAN IDs) to packets
according to customer VLAN IDs.
4. PEs select different Layer 2 tunnels according to outer VLAN tags of packets. Then
the Layer 2 protocol packets are forwarded by internal nodes on the backbone network
as common Layer 2 packets.
5. Enable Layer 2 protocol transparent transmission and QinQ on interfaces of the egress
device on the backbone network.
6. The egress device removes outer VLAN tags of the packets and forwards the packets
to user networks according to customer VLAN IDs.
As shown in Figure 11-5, PEs add outer VLAN 20 to Layer 2 protocol packets of VLAN
100 to VLAN 199 and add outer VLAN 30 to Layer 2 protocol packets of VLAN 200 to
VLAN 299, and then forward the packets to other devices on the backbone network. In this
Quidway S7700 Smart Routing Switch
Configuration Guide - Ethernet 11 Layer 2 Protocol Transparent Transmission Configuration
Issue 01 (2011-07-15) Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
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