4-20z After configuring a device as the root bridge or a secondary root bridge, you cannot change thepriority of the device.z During root bridge selection, if all devices in a spanning tree have the same priority, the one withthe lowest MAC address will be selected as the root bridge of the spanning tree.Configuring the Maximum Hops of an MST RegionBy setting the maximum hops of an MST region, you can restrict the region size. The maximum hopsconfigured on the regional root bridge will be used as the maximum hops of the MST region.The regional root bridge always sends a configuration BPDU with a hop count set to the maximumvalue. When a switch receives this configuration BPDU, it decrements the hop count by 1 and uses thenew hop count in the BPDUs it propagates. When the hop count of a BPDU reaches 0, it is discardedby the device that received it. Thus, devices beyond the reach of the maximum hop can no longer takepart in spanning tree calculation, and thereby the size of the MST region is confined.Make this configuration on the root bridge only. All the devices other than the root bridge in the MSTregion use the maximum hop value set for the root bridge.Follow these steps to configure the maximum number of hops of an MST region:To do... Use the command... RemarksEnter system view system-view —Configure the maximum hopsof the MST region stp max-hops hops Required20 by defaultConfiguring the Network Diameter of a Switched NetworkAny two terminal devices in a switched network are interconnected through a specific path composedof a series of devices. The network diameter is the number of devices on the path composed of themost devices. The network diameter is a parameter that indicates the network size. A bigger networkdiameter indicates a larger network size.Make this configuration on the root bridge only.Follow these steps to configure the network diameter of a switched network:To do... Use the command... RemarksEnter system view system-view —Configure the networkdiameter of the switchednetworkstp bridge-diameter diameter Required7 by default
