Spanning Tree Commands4-1754Command ModeInterface Configuration (Ethernet, Port Channel)Command Usage• Each spanning-tree instance is associated with a unique set of VLAN IDs.• This command is used by the multiple spanning-tree algorithm to determinethe best path between devices. Therefore, lower values should be assignedto interfaces attached to faster media, and higher values assigned tointerfaces with slower media.• Use the no spanning-tree mst cost command to specify auto-configurationmode.• Path cost takes precedence over interface priority.ExampleRelated Commandsspanning-tree mst port-priority (4-175)spanning-tree mst port-priorityThis command configures the interface priority on a spanning instance in theMultiple Spanning Tree. Use the no form to restore the default.Syntaxspanning-tree mst instance_id port-priority priorityno spanning-tree mst instance_id port-priority• instance_id - Instance identifier of the spanning tree.(Range: 0-4094, no leading zeroes)• priority - Priority for an interface. (Range: 0-240 in steps of 16)Default Setting128Command ModeInterface Configuration (Ethernet, Port Channel)Command Usage• This command defines the priority for the use of an interface in the multiplespanning-tree. If the path cost for all interfaces on a switch are the same, theinterface with the highest priority (that is, lowest value) will be configured asan active link in the spanning tree.• Where more than one interface is assigned the highest priority, the interfacewith lowest numeric identifier will be enabled.Console(config)#interface ethernet ethernet 1/5Console(config-if)#spanning-tree mst 1 cost 50Console(config-if)#
