Introduction To Bpdu Tunneling; Chapter 2 Bpdu Tunneling Configuration; Why Bpdu Tunneling; Understanding Bpdu Tunneling - H3C S7500E Series Operation Manual

Operation Manual – QinQ-BPDU Tunneling
H3C S7500E Series Ethernet Switches

Chapter 2 BPDU Tunneling Configuration

When configuring BPDU tunneling, go to these sections for information you are
interested in:

Introduction to BPDU Tunneling

Configuring BPDU Isolation
Configuring BPDU Transparent Transmission
Configuring Destination Multicast MAC Address for BPDU Tunnel Frames
BPDU Tunneling Configuration Example
2.1 Introduction to BPDU Tunneling

2.1.1 Why BPDU Tunneling

To avoid loops in your network, you can enable the spanning tree protocol (STP) on
your device. However, STP gets aware of the topological structure of a network by
means of bridge protocol data units (BPDUs) exchanged between different devices and
the BPDUs are Layer 2 multicast packets, which can be received and processed by all
STP-enabled devices on the network. This prevents each network from correctly
calculating its spanning tree. As a result, when redundant links exist in a network, data
loops will unavoidably occur.
By allowing each network to have its own spanning tree while running STP, BPDU
tunneling can resolve this problem.
BPDU tunneling can isolate BPDUs of different customer networks, so that one
network is not affected by others while calculating the topological structure.
BPDU tunneling enables BPDUs of the same customer network to be multicast
over specific VLAN VPNs in the service provider network, so that the same,
geographically dispersed customer network can implement consistent spanning
tree calculation across the service provider network.

2.1.2 Understanding BPDU Tunneling

The BPDU tunneling implements the following two functions:
BPDU isolation
BPDU transparent transmission
I. BPDU isolation
When a port receives BPDUs of other networks, the port will discard the BPDUs, so that
they will not take part in spanning tree calculation. Refer to
Chapter 2 BPDU Tunneling Configuration
2-1
Configuring BPDU Isolation.