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Catalyst 2950 and Catalyst 2955 Switch Software Configuration Guide
OL-10101-02
Chapter 13 Configuring STP
Configuring Spanning-Tree Features
Note The show spanning-tree 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 [vlan vlan-id] cost interface
configuration command. For information on how to configure load sharing on trunk ports by using
spanning-tree path costs, see the “Load Sharing Using STP” section on page 16-20.
Configuring the Switch Priority of a VLAN
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 vlan vlan-id root primary and the spanning-tree vlan vlan-id root secondary global
configuration commands to modify the switch priority.
Beginning in privileged EXEC mode, follow these steps to configure the switch priority of a VLAN. This
procedure is optional.
Step 6 show spanning-tree interface interface-id
or
show spanning-tree vlan vlan-id
Verify your entries.
Step 7 copy running-config startup-config (Optional) Save your entries in the configuration file.
Command Purpose
Command Purpose
Step 1 configure terminal Enter global configuration mode.
Step 2 spanning-tree vlan vlan-id priority priority Configure the switch priority of a VLAN.
For vlan-id, you can specify a single VLAN identified by
VLAN ID number, a range of VLANs separated by a
hyphen, or a series of VLANs separated by a comma. The
range is 1 to 4094.
For priority, the range is 0 to 61440 in increments of
4096; the default is 32768. The lower the number, the
more likely the switch will be chosen as the root switch.
Valid priority values are 4096, 8192, 12288, 16384,
20480, 24576, 28672, 32768, 36864, 40960, 45056,
49152, 53248, 57344, and 61440. All other values are
rejected.
Step 3 end Return to privileged EXEC mode.
Step 4 show spanning-tree vlan vlan-id Verify your entries.
Step 5 copy running-config startup-config (Optional) Save your entries in the configuration file.