Cisco Catalyst 3560-X Series, Software Configuration Manual

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Catalyst 3750-X and 3560-X Switch Software Configuration Guide
OL-25303-03
Chapter 1 Configuring STP
Configuring Spanning-Tree Features
To return to the default setting, use the no spanning-tree mode global configuration command. To return
the port to its default setting, use the no spanning-tree link-type interface configuration command.
Disabling Spanning Tree
Spanning tree is enabled by default on VLAN 1 and on all newly created VLANs up to the spanning-tree
limit specified in the
“Supported Spanning-Tree Instances” section on page 1-10 . Disable spanning tree
only if you are sure there are no loops in the network topology.
Caution When spanning tree is disabled and loops are present in the topology, excessive traffic and indefinite
packet duplication can drastically reduce network performance.
Beginning in privileged EXEC mode, follow these steps to disable spanning-tree on a per-VLAN basis.
This procedure is optional.
To re-enable spanning-tree, use the spanning-tree vlan vlan-id global configuration command.
Step 6
clear spanning-tree detected-protocols (Recommended for rapid-PVST+ mode only) If any port on the switch
is connected to a port on a legacy IEEE 802.1D switch, restart the
protocol migration process on the entire switch.
This step is optional if the designated switch detects that this switch is
running rapid PVST+.
Step 7 show spanning-tree summary
and
show spanning-tree interface
interface-id
Verify your entries.
Step 8 copy running-config startup-config (Optional) Save your entries in the configuration file.
Command Purpose
Command Purpose
Step 1
configure terminal Enter global configuration mode.
Step 2
no spanning-tree vlan vlan-id For vlan-id , the range is 1 to 4094.
Step 3 end Return to privileged EXEC mode.
Step 4 show spanning-tree vlan vlan-id Verify your entries.
Step 5
copy running-config startup-config (Optional) Save your entries in the configuration file.