Disabling The Spanning Tree On An Interface; Monitoring And Maintaining Fallback Bridging - Cisco WS-C3750-48PS-S Software Configuration Manual

Chapter 38 Configuring 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 a port. This
procedure is optional.
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 port, use the no bridge-group bridge-group spanning-disabled
interface configuration command.
This example shows how to disable spanning tree on a port in bridge group 10:
Switch(config)# interface gigabitethernet2/0/1
Switch(config-if)# bridge group 10 spanning-disabled

Monitoring and Maintaining Fallback Bridging

To monitor and maintain the network, use one or more of the privileged EXEC commands in
Table 38-2 Commands for Monitoring and Maintaining Fallback Bridging
Command
clear bridge bridge-group
show bridge [bridge-group] group
show bridge [bridge-group] [interface-id |
mac-address | verbose]
To display the bridge-group MAC address table on a stack member, start a session from the stack master
to the stack member by using the session stack-member-number global configuration command. Enter
the show bridge [bridge-group] [interface-id | mac-address | verbose] privileged EXEC command at the
stack member prompt.
For information about the fields in these displays, refer to the Cisco IOS Bridging and IBM Networking
Command Reference, Volume 1 of 2, Release 12.2.
78-16180-02
Purpose
Enter global configuration mode.
Specify the port, and enter interface configuration mode.
Disable spanning tree on the port.
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.
Purpose
Removes any learned entries from the forwarding
database.
Displays details about the bridge group.
Displays MAC addresses learned in the bridge group.
Catalyst 3750 Switch Software Configuration Guide
Monitoring and Maintaining Fallback Bridging
Table 38-2:
38-11