Cisco 2950G 24 Software Configuration Guide - Page 307

Chapter 12 Configuring RSTP and MSTP Configuring RSTP and MSTP Features Configuring the Port Priority If a loop occurs, the MSTP uses the port priority when selecting an interface to put into the forwarding state. You can assign higher priority values (lower numerical values) to interfaces that you want selected first and lower priority values (higher numerical values) that you want selected last. If all interfaces have the same priority 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 these steps to configure the MSTP port priority of an interface: Step 1 Step 2 Step 3 Step 4 Step 5 Step 6 Command configure terminal interface interface-id spanning-tree mst instance-id port-priority priority end show spanning-tree mst interface interface-id or show spanning-tree mst instance-id copy running-config startup-config Purpose Enter global configuration mode. Enter interface configuration mode, and specify an interface to configure. Valid interfaces include physical ports and port channels. Valid port-channel numbers are 1 to 6. Configure the port priority for an MST instance. • For instance-id, the range is 0 to 15. • For priority, the range is 0 to 255; the default is 128. The lower the number, the higher the priority. Return to privileged EXEC mode. Verify your entries. (Optional) Save your entries in the configuration file. Note The show spanning-tree mst interface interface-id privileged EXEC command displays information only if the port is in a link-up operative state. Otherwise, you can 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 mst instance-id port-priority interface configuration command. 78-14982-01 Catalyst 2950 Desktop Switch Software Configuration Guide 12-17