Chapter 33
Configuring Fallback Bridging
Changing the Forward-Delay Interval
The forward-delay interval is the amount of time spent listening for topology change information after
a port has been activated for switching and before forwarding actually begins.
Beginning in privileged EXEC mode, follow these steps to change the forward-delay interval. This
procedure is optional.
Command
Step 1
configure terminal
Step 2
bridge bridge-group forward-time
seconds
Step 3
end
Step 4
show running-config
Step 5
copy running-config startup-config
To return to the default setting, use the no bridge bridge-group forward-time global configuration
command.
This example shows how to change the forward-delay interval to 10 seconds in bridge group 10:
Switch(config)# bridge 10 forward-time 10
Changing the Maximum-Idle Interval
If a switch does not receive BPDUs from the root switch within a specified interval, it recomputes the
spanning-tree topology.
Beginning in privileged EXEC mode, follow these steps to change the maximum-idle interval (maximum
aging time). This procedure is optional.
Command
Step 1
configure terminal
Step 2
bridge bridge-group max-age seconds
Step 3
end
Step 4
show running-config
Step 5
copy running-config startup-config
To return to the default setting, use the no bridge bridge-group max-age global configuration command.
This example shows how to change the maximum-idle interval to 30 seconds in bridge group 10:
Switch(config)# bridge 10 max-age 30
78-15870-01
Purpose
Enter global configuration mode.
Specify the forward-delay interval.
For bridge-group, specify the bridge group number. The range is 1
•
to 255.
For seconds, enter a number from 4 to 200. The default is 20.
•
Return to privileged EXEC mode.
Verify your entry.
(Optional) Save your entry in the configuration file.
Purpose
Enter global configuration mode.
Specify the interval that the switch waits to hear BPDUs from the root
switch.
•
For bridge-group, specify the bridge group number. The range is 1
to 255.
•
For seconds, enter a number from 6 to 200. The default is 30.
Return to privileged EXEC mode.
Verify your entry.
(Optional) Save your entry in the configuration file.
Catalyst 3750 Metro Switch Software Configuration Guide
Configuring Fallback Bridging
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