Setting The Timeout Factor; Configuring The Bpdu Transmission Rate - HPE FlexFabric 5940 Series Configuration Manual

Step
Set the hello timer.
3.
Set the max age timer.
4.

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.
As a best practice, set the timeout factor to 5, 6, or 7 in the following situations:
•
To prevent undesired spanning tree calculations. An upstream device might be too busy to
forward configuration BPDUs in time, for example, many Layer 2 interfaces are configured on
the upstream device. In this case, the downstream device fails to receive a BPDU within the
timeout period and then starts an undesired spanning tree calculation.
•
To save network resources on a stable network.
To set the timeout factor:
Step
Enter system view.
1.
Set the timeout factor of the
2.
device.

Configuring the BPDU transmission rate

The maximum number of BPDUs a port can send within each hello time equals the BPDU
transmission rate plus the hello timer value. Configure an appropriate BPDU transmission rate based
on the physical status of the port and the network structure.
The higher the BPDU transmission rate, the more BPDUs are sent within each hello time, and the
more system resources are used. By setting an appropriate BPDU transmission rate, you can limit
the rate at which the port sends BPDUs. Setting an appropriate rate also prevents spanning tree
protocols from using excessive network resources when the network topology changes. As a best
practice, use the default setting.
To configure the BPDU transmission rate:
Step
Enter system view.
1.
Command
•
In STP/RSTP/MSTP mode:
stp timer hello time
•
In PVST mode:
stp vlan vlan-id-list timer hello
time
•
In STP/RSTP/MSTP mode:
stp timer max-age time
•
In PVST mode:
stp vlan vlan-id-list timer
max-age time
Command
system-view
stp timer-factor factor
Command
system-view
111
Remarks
The default setting is 2 seconds.
The default setting is 20 seconds.
Remarks
N/A
The default setting is 3.
Remarks
N/A