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Enabling tc-bpdu guard, Displaying and maintaining the spanning tree – H3C Technologies H3C WX3000E Series Wireless Switches User Manual

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Enabling TC-BPDU guard

When receiving topology change (TC) BPDUs (the BPDUs used to notify topology changes), the device

flushes its forwarding address entries. If someone forges TC-BPDUs to attack the device, the device

receives a large number of TC-BPDUs within a short time and is busy with forwarding address entry
flushing. This affects network stability.
With the TC-BPDU guard function, you can set the maximum number of immediate forwarding address

entry flushes that the device can perform every a certain period of time (10 seconds). For TC-BPDUs

received in excess of the limit, the device performs a forwarding address entry flush when the time period

expires. This prevents frequent flushing of forwarding address entries.
To enable TC-BPDU guard:

Step Command

Remarks

1.

Enter system view.

system-view

N/A

2.

Enable the TC-BPDU guard function.

stp tc-protection enable

Optional.
Enabled by default.

3.

Configure the maximum number of
forwarding address entry flushes that the

device can perform every 10 seconds.

stp tc-protection threshold
number

Optional.
6 by default.

NOTE:

H3C does not recommend you disable this feature.

Displaying and maintaining the spanning tree

Task Command

Remarks

Display information about ports blocked
by spanning tree protection functions.

display stp abnormal-port [ | { begin |
exclude | include } regular-expression ]

Available in any
view.

Display BPDU statistics on ports.

display stp bpdu-statistics [ interface
interface-type interface-number [ instance

instance-id ] ] [ | { begin | exclude |

include } regular-expression ]

Available in any
view.

Display information about ports shut
down by spanning tree protection

functions.

display stp down-port [ | { begin |
exclude | include } regular-expression ]

Available in any
view.

Display the historical information of port
role calculation for the specified MSTI or
all MSTIs.

display stp [ instance instance-id ] history
[ | { begin | exclude | include }
regular-expression ]

Available in any
view.

Display the statistics of TC/TCN BPDUs
sent and received by all ports in the

specified MSTI or all MSTIs.

display stp [ instance instance-id ] tc [ |
{ begin | exclude | include }

regular-expression ]

Available in any
view.

Display the spanning tree status and
statistics.

display stp [ instance instance-id ]
[ interface interface-list ] [ brief ] [ |

{ begin | exclude | include }
regular-expression ]

Available in any
view.