Cisco Catalyst 3560-X Series, Software Configuration Manual

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Catalyst 3750-X and 3560-X Switch Software Configuration Guide
OL-25303-03
Chapter 1 Configuring Fallback Bridging
Configuring Fallback Bridging
Changing the VLAN-Bridge Spanning-Tree Priority
You can globally configure the VLAN-bridge spanning-tree priority of a switch when it ties with another
switch for the position as the root switch. You also can configure the likelihood that the switch will be
selected as the root switch.
Beginning in privileged EXEC mode, follow these steps to change the switch priority. This procedure is
optional.
To return to the default setting, use the no bridge bridge-group priority global configuration command.
To change the priority on a port, 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 a port. When two switches tie for position as the root switch, you
configure a port 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. This procedure
is optional.
Command Purpose
Step 1
configure terminal Enter global configuration mode.
Step 2 bridge bridge-group priority number Change the VLAN-bridge spanning-tree 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 Specify the interface to set the priority, and enter interface
configuration mode.
Step 3 bridge-group bridge-group priority
number
Change the priority of a port.
•
For bridge-group , specify the bridge group number. The range is 1
to 255.
•
For number , enter a number from 0 to 255 in increments of 4. The
lower the number, the more likely that the port on the switch will
be chosen as the root. The default is 128.
Step 4 end Return to privileged EXEC mode.