H3C Technologies H3C S10500 Series Switches - Manual (Page 94)

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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 prevent undesired 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.
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 Layer 2 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 spanning tree protocols from using excessive network resources
when the network becomes unstable. H3C recommends you to use the default setting.
Configuring edge ports
If a port directly connects to a user terminal rather than another device or a shared LAN segment, this
port is regarded as an edge port. When network topology change occurs, an edge port will not cause
a temporary loop. Because a device does not determine whether a port is directly connected to a