PLANET WGSW-50040 - Manual (Page 161)

This delay is called the forward delay. The forward delay is co working with hello time and max age.
The parameters should meet the following conditions. Otherwise, the MSTP may work incorrectly.
2 * (Bridge_Forward_Delay - 1.0 seconds) >= Bridge_Max_Age
Bridge_Max_Age >= 2 * (Bridge_Hello_Time + 1.0 seconds)
Example:
In global mode, set MSTP forward delay time to 20 seconds.
Switch(config)#spanning-tree forward-time 20
9.1.8 spanning-tree hello-time
Command:
spanning-tree hello-time <time>
no spanning-tree hello-time
Function:
Set switch Hello time; The command “no spanning-tree hello-time” restores the default setting.
Parameter:
<time> is Hello time in seconds. The valid range is from 1 to 10.
Command mode:
Global Mode
Default:
Hello Time is 2 seconds by default.
Usage Guide:
Hello time is the interval that the switch sends BPDUs. Hello time is co working with forward delay
and max age. The parameters should meet the following conditions. Otherwise, the MSTP may
work incorrectly.
2 * (Bridge_Forward_Delay - 1.0 seconds) >= Bridge_Max_Age
Bridge_Max_Age >= 2 * (Bridge_Hello_Time + 1.0 seconds)
Example:
Set MSTP hello time to 5 seconds in global mode.
Switch(config)#spanning-tree hello-time 5
9.1.9 spanning-tree link-type p2p
Command:
spanning-tree link-type p2p {auto | force-true | force-false}
no spanning-tree link-type