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16-19
Catalyst 3550 Multilayer Switch Software Configuration Guide
78-11194-09
Chapter 16 Configuring STP
Configuring Spanning-Tree Features
Beginning in privileged EXEC mode, follow these steps to configure the cost of an interface. This
procedure is optional.
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 12-23
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
interface interface-id
Enter interface configuration mode, and specify an interface to
configure. Valid interfaces include physical interfaces and
port-channel logical interfaces (port-channel
port-channel-number).
Step 3
spanning-tree cost cost
Configure the cost for an interface.
If a loop occurs, spanning tree uses the path cost when selecting
an interface to place into the forwarding state. A lower path cost
represents higher-speed transmission.
For cost, the range is 1 to 200000000; the default value is derived
from the media speed of the interface.
Step 4
spanning-tree vlan vlan-id cost cost
Configure the cost for a VLAN.
If a loop occurs, spanning tree uses the path cost when selecting
an interface to place into the forwarding state. A lower path cost
represents higher-speed transmission.
•
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 cost, the range is 1 to 200000000; the default value is
derived from the media speed of the interface.
Step 5
end
Return to privileged EXEC mode.
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.