3Com MSR 50, MSR 30 Stp timer-factor, Syntax stp timer-factor number Undo stp timer-factor, 627

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The setting of the hello time, forward delay and max age timers must meet the following formulae.

■2 ⋅ (forward delay - 1 second) ƒ max age

■Max age ƒ 2 ⋅ (hello time + 1 second)

MSTP can work effectively on the entire network only when the above-mentioned conditions are met; otherwise, network instability will frequently occur. We recommend that you specify the network diameter in the stp bridge-diameterbridge-numbercommand and let MSTP automatically calculate an optimal setting of these three timers.

Related commands: stp timer forward-delay,stp timer hello, and 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

stp timer-factor

Syntax stp timer-factor number

undo stp timer-factor

View System view

Parameters number: Timeout factor, in the range of 1 to 20.

Description Use the stp timer-factorcommand to configure the timeout time of the device by setting the timeout factor. Timeout time = timeout factor ⋅ 3 ⋅ hello time.

Use the undo stp timer-factorcommand to restore the timeout factor to the default setting.

By default, the timeout factor of the device is set to 3.

After the network topology is stabilized, each non-root-bridge device forwards configuration BPDUs to the surrounding devices at the interval of hello time to check whether any link is faulty. Typically, if a device does not receive a BPDU from the upstream device within nine times the hello time, it will assume that the upstream device has failed and start a new spanning tree calculation process.

In a very stable network, this kind of spanning tree computing may occur because the upstream device is busy. In this case, you can avoid such unwanted spanning tree computing by lengthening the timeout time (by setting the timeout factor to 4 or more). We recommend that you set the timeout factor to 5, or 6, or 7 for a stable network.

Examples # Set the timeout factor of the device to 7.