14-18
Catalyst 2950 and Catalyst 2955 Switch Software Configuration Guide
OL-10101-02
Chapter 14 Configuring MSTP
Configuring MSTP Features
Note 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, you can 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.
Configuring the Switch Priority
You can configure the switch priority and make it more likely that the switch will be chosen as the root
switch.
Note Exercise care when using this command. For most situations, we recommend that you use the
spanning-tree mst instance-id root primary and the spanning-tree mst instance-id root secondary
global configuration commands to modify the switch priority.
Command Purpose
Step 1 configure terminal Enter global configuration mode.
Step 2 interface interface-id Specify an interface to configure, and enter interface
configuration mode. Valid interfaces include physical ports and
port channels. Valid port-channel numbers are 1 to 6.
Step 3 spanning-tree mst instance-id cost cost Configure the cost for an MST instance.
If a loop occurs, the MSTP uses the path cost when selecting an
interface to place into the forwarding state. A lower path cost
represents higher-speed transmission.
For instance-id, you can specify a single instance, a range of
instances separated by a hyphen, or a series of instances
separated by a comma. The range is 0 to 15.
For cost, the range is 1 to 200000000; the default value is
derived from the media speed of the interface.
Step 4 end Return to privileged EXEC mode.
Step 5 show spanning-tree mst interface interface-id
or
show spanning-tree mst instance-id
Verify your entries.
Step 6 copy running-config startup-config (Optional) Save your entries in the configuration file.