Reference Guide

Spanning Tree Commands 763
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.
RSTP provides BPDU protection function against such attack. After BPDU
protection function is enabled on a switch, the system disables an edge port
that has received BPDU and notifies the network manager about it. The
disabled port can only be enabled by the no version of the command.
Syntax
spanning-tree bpdu-protection
no spanning-tree bpdu-protection
Default Configuration
BPDU protection is not enabled.
Command Mode
Global Configuration mode
User Guidelines
This command has no user guidelines.
Example
The following example enables BPDU protection.
console(config)#spanning-tree bpdu-protection
spanning-tree cost
Use the spanning-tree cost command in Interface Configuration mode to
configure the external spanning-tree path cost for a port. To return to the
default port path cost, use the no form of this command.
2CSPC4.XModular-SWUM204.book Page 763 Friday, March 15, 2013 9:24 AM