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The set protocols spanning-tree stp max-age command sets the BPDU aging time on the switching device when STP is running.

Command Syntax

set protocols spanning-tree stp max-age <max-age>




max-age <max-age>

Specifies the BPDU aging time. The value is an integer, in seconds, that ranges from 6 to 40. The default value is 20s.

Usage Guidelines

Max Age is the maximum lifetime of the BPDU packets. If the received BPDUs time out, the switching device ages the BPDUs and blocks the port that receives the BPDUs.


The relationships between the Hello Time, Forward Delay, and Max Age are as follows. The spanning tree functions properly only if the relationships are correctly established. Otherwise, network flapping occurs.

  •   2 x (Forward Delay - 1.0) ≥ Max Age
  •   Max Age ≥ 2 x (Hello Time + 1.0)


  • Set BPDU aging time to 15s when STP is running.
admin@Xorplus# set protocols spanning-tree stp max-age 15
admin@Xorplus# commit
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