3Com SuperStack 4 Configuration Manual page 238

250 C 10: RSTP C
HAPTER
Set Max Age of the
Specified Bridge
Set Timeout Factor of
the Bridge
ONFIGURATION
Table 272 Set Hello Time of the Specified Bridge
Operation
Set Hello Time of the specified bridge
Restore the default Hello Time of the specified
bridge
An appropriate Hello Time can ensure that the bridge can detect certain link
failures in the network in a timely manner. It is strongly recommended that default
value of 2 seconds is retained.
By default, the Hello Time of the bridge is 2 seconds.
Max Age is a parameter to judge whether the configuration BPDU is "timeout".
Users can configure it according to the actual network situation.
You can use the following command to set Max Age of a specified bridge.
Perform the following configuration in System View.
Table 273 Set Max Age of the Specified Bridge
Operation
Set Max Age of the specified bridge
Restore the default Max Age of the specified bridge
If the Max Age is too short, it will result in frequent calculation of spanning tree or
misjudge the network congestion as a link fault. On the other hand, too long Max
Age may make the bridge unable to find link failure in time and weaken the
network auto-sensing ability. It is recommended to use the default setting.
By default, the bridge Max Age is 20 seconds.
A bridge transmits hello packet regularly to the adjacent bridges to check if there
is link failure. Generally, if the Switch does not receive the RSTP packets from the
upstream Switch for 3 occurences of hello time, the Switch will decide the
upstream Switch is dead and will recalculate the topology of the network. Then in
a steady network, the recalculation may be caused when the upstream Switch is
busy. In this case, you can redefine the timeout interval to a longer time by
defining the multiple value of hello time.
You can use the following command to set the multiple value of hello time of a
specified bridge.
Perform the following configurations in System View.
Table 274 Set Timeout Factor of the Bridge
Operation
Set the multiple value of hello time of a specified bridge
Restore the default multiple value of hello time
It is recommended to set 5, 6 or 7 as the value of multiple in the steady network.
Command
stp timer hello centiseconds
undo stp timer hello
Command
stp timer max-age
centiseconds
undo stp timer max-age
Command
stp timeout-factor
undo stp timeout-factor
number