Configuring the timeout factor
The timeout factor is a parameter used to decide the timeout time in the following formula: Timeout time
= timeout factor × 3 × hello time.
After the network topology is stabilized, each non-root-bridge device forwards configuration BPDUs to
the downstream devices at the interval of hello time to determine whether any link is faulty. 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 and starts a new spanning tree calculation process.
Sometimes 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.
In a stable network, you can avoid such unwanted spanning tree calculations by setting the timeout factor
to 5, 6, or 7.
Follow these steps to configure the timeout factor:
To do...
Use the command...
Remarks
Enter system view
system-view
—
Configure the timeout factor of the device
stp timer-factor
factor
Required
3 by default.
Configuring the maximum port rate
The maximum rate of a port refers to the maximum number of BPDUs the port can send within each hello
time. The maximum rate of a port is related to the physical status of the port and the network structure.
Make this configuration on the root bridge and on the leaf nodes separately.
Follow these steps to configure the maximum rate of a port or a group of ports:
To do...
Use the command...
Remarks
Enter system view
system-view
—
Enter Ethernet interface
view or Layer 2
aggregate interface view
interface
interface-type
interface-number
Enter interface
view or port
group view
Enter port group view
port-group manual
port-group-name
Required
Use either command.
Configure the maximum rate of the ports
stp transmit-limit
limit
Required
10 by default.
NOTE:
The higher the maximum port rate is, the more BPDUs will be sent within each hello time, and the more
system resources will be used. By setting an appropriate maximum port rate, you can limit the rate at
which the port sends BPDUs and prevent MSTP from using excessive network resources when the network
becomes unstable. HP recommends that you use the default setting.
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