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The set protocols spanning-tree mstp interface tcn-guard command configures TCN (Topology Change Notification) guard on a physical port or a LAG port for MSTP mode.

Command Syntax

set protocols spanning-tree mstp interface <interface-name> tcn-guard <true | false>




interface <interface-name>

Specifies a port name. The value is a string that can be set to a physical port name or a LAG port.

tcn-guard <true | false>

Enables or disables TCN-guard on a port. The value could be true or false.

  •   true: enables TCN-guard.
  •   false: disables TCN-guard.

By default, TCN-guard is disabled.

Usage Guidelines

TCN BPDU is generated when the switch detects a change in the spanning tree topology. If the switch receives many TCN BPDUs in a short period of time, the spanning tree recalculates frequently, causing a large burden on the device and affecting the stability of the network.

After the TCN guard function is enabled, the switch processes only a certain number of topology change packets in a certain period.


  • Enable TCN guard on the port ge-1/1/1 for MSTP mode.
admin@Xorplus# set protocols spanning-tree mstp interface ge-1/1/1 tcn-guard true
admin@Xorplus# commit

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