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| 3.8 |  | RSTP and MST Configuration |
| 3.8.6 |  | Configuring MST path cost |

The MSTP path cost default value is derived from the media speed of an interface. If a loop occurs, the MSTP uses cost when selecting an interface to put in the Forwarding state. Assign lower cost values to interfaces that the network administrator wants selected first and higher cost values to interfaces that the administrator wants selected last. If all interfaces have the same cost value, the MSTP puts the interface with the lowest interface number in the Forwarding state and blocks the other interfaces.

Beginning in privileged EXEC mode, follow the steps outlined in Figure to configure the MSTP cost of an interface.

The show spanning-tree mst interface interface-id privileged EXEC command displays information only for ports that are in a link-up operative state. Otherwise, use the show running-config privileged EXEC command to confirm the configuration.

To return the interface to its default setting, use the no spanning-tree mst instance-id cost interface configuration command.