Cisco 15327 - Manual (Page 124)

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Ethernet Card Software Feature and Configuration Guide, R7.2
Chapter 7 Configuring STP and RSTP
Configuring the Path Cost
To return the interface to its default setting, use the no bridge-group id bridge-group-number priority-
value command.
Configuring the Path Cost
The spanning-tree path cost default value is derived from the media speed of an interface. If a loop
occurs, spanning tree uses cost when selecting an interface to put in the forwarding state. You can assign
lower cost values to interfaces that you want selected first and higher cost values to interfaces that you
want selected last. If all interfaces have the same cost value, spanning tree 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 cost of an interface:
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 bridge-group bridge-group-number path-cost
cost command.
Step 3 Router(config-if)# bridge-group
bridge-group-number priority-value
Configures the port priority for an interface that is an
access port.
For the priority-value, the range is 0 to 255; the default is
128 in increments of 16. The lower the number, the higher
the priority.
Step 4 Router(config-if)# end Return to privileged EXEC mode.
Command Purpose
Command Purpose
Step 1 Router# configure terminal Enters the global configuration mode.
Step 2 Router(config)# interface
interface-id
Enters the interface configuration mode and specifies an
interface to configure.
Valid interfaces include physical interfaces and port-channel
logical interfaces (port-channel port-channel-number).
Step 3 Router(config-if)# bridge-group
bridge-group-number path-cost
cost
Configures the cost for an interface that is an access port.
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 0 to 65535; the default value is derived
from the media speed of the interface.
Step 4 Router(config-if)# end Returns to the privileged EXEC mode.