8.5.3 Configuring TC Protection on a Switching Device
After TC protection is enabled, you can set the number of times an MSTP process processes TC
BPDUs within a given time. TC protection avoids frequent deletion of MAC address entries and
ARP entries, thereby protecting switching devices.
Context
Attackers may send pseudo TC BPDUs to attack switching devices. Switching devices receive
a large number of TC BPDUs in a short time and delete entries frequently, which burdens system
processing and degrades network stability.
TC protection is used to suppress TC BPDUs. You can configure the number of times a switching
device processes TC BPDUs within a given time period. If the number of TC BPDUs that the
switching device receives within a given time exceeds the specified threshold, the switching
device processes only the specified number of TC BPDUs. After the specified time period
expires, the device processes the excess TC BPDUs for once. This function prevents the
switching device from frequently deleting MAC entries and ARP entries, saving CPU resources.
Procedure
Step 1
Run:
system-view
The system view is displayed.
Step 2
Run:
stp tc-protection
TC protection is enabled for the MSTP process.
By default, TC protection is not enabled on the switching device.
Step 3
Run:
stp tc-protection threshold
threshold
The number of times the MSTP process handles the received TC BPDUs and updates forwarding
entries within a given time is set.
NOTE
The given time is specified by the MSTP Hello timer set by using the
stp timer hello
hello-time
command.
----End
8.5.4 Configuring Root Protection on an Interface
The root protection function on a switching device protects a root bridge by preserving the role
of a designated port.
Context
Due to incorrect configurations or malicious attacks on the network, a root bridge may receive
BPDUs with a higher priority. Consequently, the legitimate root bridge is no longer able to serve
as the root bridge and the network topology is changed, triggering spanning tree recalculation.
This also may cause the traffic that should be transmitted over high-speed links to be transmitted
Huawei AR3200 Series Enterprise Routers
Configuration Guide - LAN
8 MSTP Configuration
Issue 02 (2012-03-30)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
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