3com 8807 참조 가이드

When you configure Hello time, Forward Delay and Max Age, remember to 
guarantee the following equations:

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

Max Age >= 2 x (Hello Time + 1.0 second)

Only if the earlier-mentioned formulas are equal can the MSTP normally operate 
on the entire network. Otherwise, the network may flap frequently. You are 
recommended to use the stp bridge-diameter command to specify the diameter 
of the switching network, so that MSTP can automatically calculate and give the 
moderate values for the time parameters.

Related command: stp timer forward-delay, stp timer hello, stp 
bridge-diameter.

# Set Max Age of the device to 1000 centiseconds.

<SW8800>system-view

 

System View: return to User View with Ctrl+Z.

 

[SW8800] stp timer max-age 1000 

stp timer-factor number

System view

number: Specifies the multiple of hello time, in the range of 1 to 10. The default 
value is 3.

Use the stp timer-factor command to configure the multiple of hello time for the 
switch.

Use the undo stp timer-factor command to restore the default multiple value.

The Ethernet switch transmits STP packets every hello time. Generally, if the switch 
does not receive the STP packets from the upstream switch for three times of hello 
time, the switch will decide the upstream switch is dead and will recalculate the 
topology of the network. Then in steady network, the recalculation may be caused 
when the upstream is busy. In this case, users can redefine the timeout interval to 
a longer time (four times the hello time or larger) by define the multiple of hello 
time. It is recommended to set 5, 6 or 7 as the value of multiple in the steady 
network.

# Set the multiple value of hello time to 7.