Stp Timer Max-Age - 3Com 8807 Command Reference Manual

206 C 13: MSTP C C
HAPTER ONFIGURATION OMMANDS
timeouts. The root bridge transmits BPDU packets at an interval as you
configured, while other switches apply the Hello Time configured on the root
bridge.
When configuring 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 max-age, stp
bridge-diameter.
Example
# Set Hello Time of the switch to 400 centiseconds.
<SW8800>system-view
System View: return to User View with Ctrl+Z
[SW8800] stp timer hello 400

stp timer max-age

Syntax
stp timer max-age centi-senconds
undo stp timer max-age
View
System view
Parameter
centi-seconds: Specifies the Max Age, which is in the range from 600 to 4000 and
measured with centiseconds. By default, the Max Age of the switch is 2000
centiseconds.
Description
Use the stp timer max-age command to configure the Max Age of the switch.
Use the undo stp timer max-age command to restore the default Max Age.
MSTP can detect the link fault and automatically resume the forwarding state of
the redundant link. On the CIST, the switch checks if the configuration BPDU
received via the port expires according to the Max Age. If the BPDU expires, the
MSTI has to be calculated again.
Max Age takes no effect on MSTIs. If the current switch is CIST root bridge, it will
check if the configuration BPDU expires according to the configured Max Age.
Otherwise, the switch adopts the Max Age configured on the CIST root bridge.