Command Line Interface Guide

754 Spanning Tree Commands
spanning-tree bpdu flooding
The spanning-tree bpdu flooding command allows flooding of BPDUs
received on non-spanning-tree ports to all other non-spanning-tree ports. Use
the “no” form of the command to disable flooding.
Syntax
spanning-tree bpdu flooding
no spanning-tree bpdu flooding
Default Configuration
This feature is disabled by default.
Command Mode
Global Configuration mode
Usage Guidelines
There are no usage guidelines for this command.
Example
console#spanning-tree bpdu flooding
spanning-tree bpdu-protection
Use the spanning-tree bpdu-protection command in Global Configuration
mode to enable BPDU protection on a switch. Use the no form of this
command to resume the default status of BPDU protection function.
For an access layer device, the access port is generally connected to the user
terminal (such as a desktop computer) or file server directly and configured as
an edge port to implement the fast transition. When the port receives a
BPDU packet, the system sets it to non-edge port and recalculates the
spanning tree, which causes network topology flapping. In normal cases, these
ports do not receive any BPDU packets. However, someone may forge BPDU
to maliciously attack the switch and cause network flapping.
2CSPC4.X8100-SWUM100.book Page 754 Wednesday, August 29, 2012 6:23 PM