Stp Timer Max-Age - 3Com S7906E Command Reference Manual

Examples
# Set the hello time of the device to 400 centiseconds.
<Sysname> system-view
[Sysname] stp timer hello 400

stp timer max-age

Syntax
stp timer max-age centi-seconds
undo stp timer max-age
View
System view
Default Level
2: System level
Parameters
centi-seconds: Max age (in centiseconds), ranging from 600 to 4000 in steps of 100.
Description
Use the stp timer max-age command to set the max age timer of the device.
Use the undo stp timer max-age command to restore the system default.
By default, the max age is set to 2,000 centiseconds.
MSTP can detect link failures and automatically restore the forwarding state of the redundant link. In the
CIST, the device determines whether a configuration BPDU received on a port has expired based on
the max age timer. If a port receives a configuration BPDU that has expired, that MSTI needs to be
re-computed.
The max age timer is not meaningful for MSTIs. If the current device is the root bridge of the CIST, it
determines whether a configuration BPDU has expired based on the configured max age timer; if the
current device is not the root bridge of the CIST, it uses the max age timer set on the CIST root bridge.
The settings of the hello time, forward delay and max age timers must meet the following formulae:
2 × (forward delay – 1 second) ú max age
Max age ú 2 × (hello time + 1 second)
MSTP can work effectively on the entire network only when the above-mentioned conditions are met;
otherwise, topology changes will frequently occur. We recommend that you specify the network
diameter in the stp root primary command and let MSTP automatically calculate an optimal setting of
these three timers.
Related commands: stp timer forward-delay, stp timer hello, stp bridge-diameter.
Examples
# Set the max age timer of the device to 1,000 centiseconds.
<Sysname> system-view
[Sysname] stp timer max-age 1000
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