Setting the timeout factor
The timeout factor is a parameter used to decide the timeout period. The formula for calculating the timeout period is: timeout period = timeout factor × 3 × hello time.
In a stable network, each non-root-bridge device forwards configuration BPDUs to the downstream devices at the hello time interval to detect link failures. If a device does not receive a BPDU from the upstream device within nine times the hello time, it assumes that the upstream device has failed. Then, it starts a new spanning tree calculation process.
A device might fail to receive a BPDU from the upstream device because the upstream device is busy. If a spanning tree calculation occurs, the calculation can fail and also waste network resources. On a stable network, you can prevent undesired spanning tree calculations by setting the timeout factor to 5, 6, or 7.
To set the timeout factor:
Step | Command | Remarks |
|---|---|---|
1. Enter system view. | system-view | N/A |
2. Set the timeout factor of the device. | stp timer-factor factor | The default setting is 3. |