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Catalyst 3550 Multilayer Switch Software Configuration Guide
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Chapter 26 Configuring Fallback Bridging
Configuring Fallback Bridging
Changing the Switch Priority
You can globally configure the priority of an individual switch when two switches tie for position as the
root switch, or you can configure the likelihood that a switch will be selected as the root switch. This
priority is determined by default; however, you can change it.
Beginning in privileged EXEC mode, follow these steps to change the switch priority:
No no form of this command exists. To return to the default setting, use the bridge bridge-group
priority number global configuration command, and set the priority to the default value. To change the
priority on an interface, use the bridge-group priority interface configuration command (described in
the next section).
This example shows how to set the switch priority to 100 for bridge group 10:
Switch(config)# bridge 10 priority 100
Changing the Interface Priority
You can change the priority for an interface. When two switches tie for position as the root switch, you
configure an interface priority to break the tie. The switch with the lowest interface value is elected.
Beginning in privileged EXEC mode, follow these steps to change the interface priority:
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
bridge bridge-group priority number
Change the priority of the switch.
•
For bridge-group, specify the bridge group number. The range is 1
to 255.
•
For number, enter a number from 0 to 65535. The default is 32768.
The lower the number, the more likely the switch will be chosen as
the root.
Step 3
end
Return to privileged EXEC mode.
Step 4
show running-config
Verify your entry.
Step 5
copy running-config startup-config
(Optional) Save your entry in the configuration file.
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
interface interface-id
Enter interface configuration mode, and specify the interface to set the
priority.
Step 3
bridge-group bridge-group priority
number
Change the priority of an interface.
•
For bridge-group, specify the bridge group number. The range is 1
to 255.
•
For number, enter a number from 0 to 255. The lower the number,
the more likely that the interface on the switch will be chosen as the
root. The default is 128.
Step 4
end
Return to privileged EXEC mode.
