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Catalyst2950 Desktop Switch Software Configuration Guide
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Chapter11 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 v alues ( lo wer num erical v alues ) to interf aces t hat you w ant selected
first and lower priority values (higher numerical val ues) that y ou want sel ected last . If all interfa ces ha ve
the same priority value, the MSTP puts the interface with the lowest interf a ce number in t he for w ar ding
state and blocks the other interfaces.
Beginning in privileged EXEC mode, follow these steps to configure the MSTP port priority of an
interface:
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.
Command Purpose
Step1 configure terminal Enter global configuration mode.
Step2 interface interface-id 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.
Step3 spanning-tree mst instance-id port-priority priority 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.
Step4 end Return to privileged EXEC mode.
Step5 show spanning-tree mst interface interface-id
or
show spanning-tree mst instance-id
Verify your entries.
Step6 copy running-config startup-config (Optional) Save your entries in the configuration file.