Bpdu Tunneling; Introduction To Bpdu Tunneling - 3Com Switch 4800G 24-Port Configuration Manual

15
Introduction to BPDU
Tunneling
Why BPDU Tunneling
How BPDU Tunneling
Works
BPDU T
UNNELING
When configuring BPDU tunneling, go to these sections for information you are
interested in:
"Introduction to BPDU Tunneling" on page 141
■
"Configuring BPDU Isolation" on page 142
■
"Configuring BPDU Transparent Transmission" on page 143
■
"Configuring Destination Multicast MAC Address for BPDU Tunnel Frames" on
■
page 144
"BPDU Tunneling Configuration Example" on page 144
■
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 broadcast
■
in a specific VLAN in the provider network, so that the geographically dispersed
customer networks of the same customer can implement consistent spanning
tree calculation across the provider network.
The BPDU tunneling implements the following two functions:
BPDU isolation
■
BPDU transparent transmission
■
The work process of IGMP is as follows:
C
ONFIGURATION