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| 3.6 |  | STP Configuration |
| 3.6.4 |  | Setting the priority for ports and VLANs |

If a loop occurs, spanning tree uses the port priority when selecting an interface to put into the Forwarding state. Assign higher priority values (lower numerical values) to interfaces that the network administrator prefers to have selected first and lower priority values (higher numerical values) that the network administrator wants selected last. If all interfaces have the same priority value, spanning tree puts the interface with the lowest interface number in the Forwarding state and blocks the other interfaces.

Cisco IOS uses the port priority value when the interface is configured as an access port and uses VLAN port priority values when the interface is configured as a trunk port.

Beginning in privileged EXEC mode, follow these steps to configure the port priority of an interface.

The show spanning-tree interface interface-id privileged EXEC command displays information only if the port is in a link-up operative state. Otherwise, use the show running-config interface privileged EXEC command to confirm the configuration.

To return the interface to its default setting, use the no spanning-tree [vlan vlan-id] port-priority interface configuration command.