Disabling The Spanning Tree On An Interface - Cisco Catalyst 3550 series Software Configuration Manual

Monitoring and Maintaining Fallback Bridging

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 example, when switched LAN subnetworks are
separated by a WAN, BPDUs can be prevented from traveling across the WAN link.
Beginning in privileged EXEC mode, follow these steps to disable spanning tree on an interface:
Command
Step 1
configure terminal
Step 2
interface interface-id
Step 3 bridge-group bridge-group
spanning-disabled
Step 4
end
Step 5
show running-config
Step 6
copy running-config startup-config
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 interface in bridge group 10:
Switch(config)# interface gigabitethernet0/1
Switch(config-if)# bridge group 10 spanning-disabled
Monitoring and Maintaining Fallback Bridging
To monitor and maintain fallback bridging, use one or more of the privileged EXEC commands in
Table
Table 36-2 Commands for Monitoring and Maintaining Fallback Bridging
Command
clear bridge bridge-group
show bridge [bridge-group]
show bridge [bridge-group] [interface-id]
[address] [group] [verbose]
For information about the fields in these displays, refer to the Cisco IOS Bridging and IBM Networking
Command Reference for Release 12.1.
Catalyst 3550 Multilayer Switch Software Configuration Guide
36-12
Purpose
Enter global configuration mode.
Enter interface configuration mode, and specify the interface ID.
Disable spanning tree on the interface.
For bridge-group, specify the bridge group number. The range is 1
to 255.
Return to privileged EXEC mode.
Verify your entry.
(Optional) Save your entry in the configuration file.
36-2:
Chapter 36
Purpose
Removes any learned entries from the forwarding
database and clears the transmit and receive counts for
any statically configured entries.
Displays details about the bridge group.
Displays classes of entries in the bridge forwarding
database.
Configuring Fallback Bridging
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