26-12
Catalyst 3550 Multilayer Switch Software Configuration Guide
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Chapter26 Configuring Fallback Bridging
Monitoring and Maintaining the Network

Disabling the Spanning Tree on an Interface

When a loop-free path exists between any two switched subnetworks, you can prevent BPDUs generated
in one switching subnetwork from impacting devices in the other switching subnetwork, yet still permit
switching throughout the network as a whole. For exampl e, w h en sw it ched L AN subnet wor ks a re
separated by a WAN, BPDUs can be prevented from traveling across the WAN link.
Beginning in privileged EXEC mode, follow these steps to disable span ni ng t ree on an in terf ac e:
To re-enable spanning tree on the interface, use the no bridge-group bridge-group spanning-disabled
interface configuration command.
This example shows how to disable spanning tree on an interfac e i n brid ge group 10 :
Switch(config)# interface gigabitethernet0/1
Switch(config-if)# bridge group 10 spanning-disabled
Monitoring and Maintaining the Network
To monitor and maintain the network, use one or more of the privileged EXEC commands in Ta ble 26- 2:
Command Purpose
Step1 configure terminal Enter global configuration mode.
Step2 interface interface-id Enter interface configuration mode, and specify the interface ID.
Step3 bridge-group bridge-group
spanning-disabled Disable spanning tree on the interface.
For bridge-group, specify the bridge group number. The range is 1
to 255.
Step4 end Return to privileged EXEC mode.
Step5 show running-config Verify your entry.
Step6 copy running-config startup-config (Optional) Save your entry in the configuration file.
Table26-2 Fallback Bridging Commands for Monitoring and Maintaining the Network
Command Purpose
clear bridge bridge-group Removes any learned entries from the forwarding
database and clears the transmit and receive counts for
any statically configured entries.
show bridge [bridge-group] Displays details about the bridge group.
show bridge [bridge-group] [interface-id]
[address] [group] [verbose]Displays classes of entries in the bridge forwarding
database.