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Catalyst 3550 Multilayer Switch Software Configuration Guide
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Chapter26 Configuring Fallback Bridging
Configuring Fallback Bridging
Adjusting BPDU Intervals
You can adjust BPDU intervals as described in these sections:
Adjusting the Interval between Hello BPDUs
Defining the Forward Delay Interval
Defining the Maximum Idle Interval
Note Each switch in a spanning tree adopts the interval between hello BPDUs, the forward delay interval,
and the maximum idle interval parameters of the root switch, regardless of what its individual
configuration might be.

Adjusting the Interval between Hello BPDUs

Beginning in privileged EXEC mode, follow these step to adjust the interval between hello BPDUs:
To return to the default setting, use the no bridge bridge-group hello-time global configuration
command.
This example shows how to change the hello interval to 5 secon ds in br idge grou p 10:
Switch(config)# bridge 10 hello-time 5

Changing the Forward-Delay Interval

The forward-delay interval is the amount of time spen t l iste ning f or topol og y cha ng e info rma tion af ter
an interface has been activated for switching and be fore f orwa rdin g a ctu all y be gins.
Beginning in privileged EXEC mode, follow these steps to change the forward-delay interval:
Command Purpose
Step1 configure terminal Enter global configuration mode.
Step2 bridge bridge-group hello-time seconds Specify the interval between hello BPDUs.
For bridge-group, specify the bridge group number. The range is 1
to 255.
For seconds, enter a number from 1 to 10. The default is 2 seconds.
Step3 end Return to privileged EXEC mode.
Step4 show running-config Verify your entry.
Step5 copy running-config startup-config (Optional) Save your entry in the configuration file.
Command Purpose
Step1 configure terminal Enter global configuration mode.
Step2 bridge bridge-group forward-time
seconds 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 10 to 200. The defa ult is 20
seconds.