1-20 system-view[Sysname] stp mode stpConfiguring the Priority of the Current DeviceThe priority of a device determines whether it can be elected as the root bridge of a spanning tree. Alower value indicates a higher priority. By setting the priority of a device to a low value, you can specifythe device as the root bridge of the spanning tree. An MSTP-enabled device can have different prioritiesin different MSTIs.Configuration procedureFollow these steps to configure the priority of the current device in a specified MSTI:To do... Use the command... RemarksEnter system view system-view —Configure the priority of thecurrent device in a specifiedMSTIstp [ instance instance-id ]priority priorityOptional32768 by defaultz After specifying the current device as the root bridge or a secondary root bridge, you cannotchange the priority 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.Configuration example# Set the device priority in MSTI 1 to 4096. system-view[Sysname] stp instance 1 priority 4096Configuring 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 maximum value.When a switch receives this configuration BPDU, it decrements the hop count by 1 and uses the newhop count in the BPDUs it propagates. When the hop count of a BPDU reaches 0, it is discarded by thedevice that received it. Thus, devices beyond the reach of the maximum hop can no longer take part inspanning tree calculation, and thereby the size of the MST region is confined.All the devices other than the root bridge in the MST region use the maximum hop value set for the rootbridge.
