Note Exercise care when using this command. For normal network configurations, we recommend that you use the spanning-tree mst i nstance-id root primary and the spanning-tree mst instance-id root secondary global configuration commands to specify a device as the root or secondary root device. You should modify the device priority only in circumstances where these commands do not work. To configure the device priority, perform this procedure: Before you begin • An MST must be specified and enabled on the device. • You must also know the specified MST instance ID used.
Procedure Configuring Multiple Spanning-Tree Protocol (Optional) Configuring the Device Priority Command or Action Purpose Step 1 enable Example: Device> enable Enables privileged EXEC mode. Enter your password if prompted. Step 2 configure terminal Example: Device# configure terminal Enters global configuration mode. Step 3 spanning-tree mst instance-id priority priority Example: Device(config)# spanning-tree mst 0 priority 40960 Configures the device priority. • For instance-id, you can specify a single instance, a range of instances separated by a hyphen, or a series of instances separated by a comma. The range is 0 to 4094.
• For priority, the range is 0 to 61440 in increments of 4096; the default is 32768. The lower the number, the more likely the device will be chosen as the root switch. Priority values are 0, 4096, 8192, 12288, 16384, 20480, 24576, 28672, 32768, 36864, 40960, 45056, 49152, 53248, 57344, and 61440. These are the only acceptable values. Step 4 end Example: Device(config-if)# end Returns to privileged EXEC mode. Configuring Multiple Spanning-Tree Protocol 22