H3C Technologies H3C WX5500E Series Access Controllers - Manual (Page 88)

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Configuring the timeout factor
The timeout factor is a parameter used to calculate the timeout time in the following formula: Timeout time
= timeout factor × 3 × hello time.
After the network topology stabilizes, each non-root-bridge device forwards configuration BPDUs to
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 default timeout factor x 3) 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. In this case, a spanning tree calculation occurs, the calculation can fail and also waste network
resources. In a stable network, you can prevent undesired spanning tree calculations by setting the
timeout factor to 5, 6, or 7, resulting in a longer timeout time.
To configure the timeout factor:
Step Command Remarks
1. Enter system view. system-view N/A
2. Configure the timeout factor
of the device.
stp timer-factor factor The default setting is 3.
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.
The higher the maximum port rate, 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 spanning tree protocols from using excessive network resources
when the network becomes unstable. H3C recommends you to use the default setting.
To configure the maximum rate of a port or a group of ports:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter interface view or port
group view.
• Enter Layer 2 Ethernet interface view or
Layer 2 aggregate interface view:
interface interface-type
interface-number
• Enter port group view:
port-group manual port-group-name
Use one of the commands.
3. Configure the maximum rate
of the ports.
stp transmit-limit limit The default setting is 10.