H3C Technologies H3C S12500-X Series Switches - Manual (Page 107)

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Enabling TC-BPDU guard
When a device receives topology change (TC) BPDUs (the BPDUs that notify devices of topology
changes), it flushes its forwarding address entries. If someone forges TC-BPDUs to attack the device, the
device will receive a large number of TC-BPDUs within a short time and be 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 within a specified period of time (10 seconds) after it receives
the first TC-BPDU. 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
By default, TC-BPDU guard is
enabled.
H3C recommends not
disabling this feature.
3. (Optional.) Configure the maximum
number of forwarding address entry
flushes that the device can perform every
10 seconds.
stp tc-protection threshold
number
The default setting is 6.
Displaying and maintaining the spanning tree
Execute display commands in any view and reset command in user view.
Task Command
Display information about ports blocked by spanning tree
protection functions.
display stp abnormal-port
Display BPDU statistics on ports.
display stp bpdu-statistics [ interface
interface-type interface-number [ instance
instance-list ] ]
Display information about ports shut down by spanning
tree protection functions.
display stp down-port
Display the historical information of port role calculation
for the specified MSTI or all MSTIs (in standalone mode). display stp [ instance instance-list ] history [ slot
slot-number ]
Display the historical information of port role calculation
for the specified MSTI or all MSTIs (in IRF mode). display stp [ instance instance-list ] history [ chassis
chassis-number slot slot-number ]
Display the statistics of TC/TCN BPDUs sent and received
by all ports in the specified MSTI or all MSTIs (in
standalone mode).
display stp [ instance instance-list ] tc [ slot
slot-number ]