Setting STP/RSTP 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.
Set the Forward Delay timer, Hello timer, and Max Age timer.
1. Run stp timer forward-delay forward-delay
  The Forward Delay timer is set for the device.
  
  By default, the Forward Delay timer is 1500 centiseconds (15 seconds).
2. Run stp timer hello hello-time
  The Hello timer is set for the device.
  
  By default, the Hello timer is 200 centiseconds (2 seconds).
3. Run stp timer max-age max-age
  The Max Age timer is set for the device.
  
  By default, the Max Age timer is 2000 centiseconds (20 seconds).