69NOTE:• The length of the forward delay timer is related to the network diameter of the switched network. Thelarger the network diameter is, the longer the forward delay time should be. If the forward delay timeris too short, temporary redundant paths might occur. If the forward delay timer is too long, networkconvergence might take a long time. H3C recommends you to use the default setting.• An appropriate hello time setting enables the device to promptly detect link failures on the networkwithout using excessive network resources. If the hello time is too long, the device will mistake packet lossas a link failure and trigger a new spanning tree calculation process. If the hello time is too short, thedevice will frequently send the same configuration BPDUs, which add the device burden and wastenetwork resources. H3C recommends you to use the default setting.• If the max age timer is too short, the device will frequently launch spanning tree calculation and maymistake network congestion as a link failure. If the max age timer is too long, the device may fail todetect link failures and launch spanning tree calculations promptly, reducing the auto-sensing capabilityof the network. H3C recommends you to use the default setting.Configuring the timeout factorThe 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 tothe downstream devices at the interval of hello time to determine whether any link is faulty. If a devicedoes not receive a BPDU from the upstream device within nine times the hello time, it assumes that theupstream 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 deviceis busy. If a spanning tree calculation occurs, the calculation can fail and also waste the networkresources. In a stable network, you can prevent undesired spanning tree calculations by setting thetimeout factor to 5, 6, or 7.Follow these steps to configure the timeout factor:To do… Use the command… RemarksEnter system view system-view —Configure the timeout factor of thedevice stp timer-factor factor RequiredThe default setting is 3.Configuring the maximum port rateThe maximum rate of a port refers to the maximum number of BPDUs the port can send within each hellotime. 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… RemarksEnter system view system-view —
