Setting the Values of MSTP Timers

Context

There are three timers used in spanning tree calculation: Forward Delay timer, Hello timer, and Max Age timer. These timers can be configured to affect STP convergence. However, you are not advised to directly change these timers. Instead, it is recommended that you set the network diameter so that the spanning tree protocol automatically adjusts these timers in accordance with the network scale. When the default network diameter is used, the default values of the three parameters are used.

To prevent frequent network flapping, ensure that the values of the Hello timer, Forward Delay timer, and Max Age timer of the root switch conform to the following formulas:

2 x (Forward Delay timer - 1.0 second) >= Max Age timer
Max Age timer >= 2 x (Hello timer + 1.0 second)

Procedure

Run system-view
The system view is displayed.
(Optional) Run stp process process-id
The MSTP process view is displayed.

Skip this step if you perform configurations in the MSTP process 0.
Set Forward Delay, Hello Time, and Max Age.
1. Run stp timer forward-delay forward-delay
  The value of Forward Delay of the switch is set.
  
  By default, the value of Forward Delay of the switch is 1500 centiseconds.
2. Run stp timer hello hello-time
  The value of Hello Time of the switch is set.
  
  By default, the value of Hello Time of the switch is 200 centiseconds.
3. Run stp timer max-age max-age
  The value of Max Age of the switch is set.
  
  By default, the value of Max Age of the switch is 2000 centiseconds.