Specifications

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Catalyst 2950 and Catalyst 2955 Switch Command Reference
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Chapter 2 Cisco IOS Commands
spanning-tree mode
spanning-tree mode
Use the spanning-tree mode global configuration command to enable either per-VLAN spanning-tree
(PVST) or multiple spanning tree (MST) on your switch. Use the no form of this command to return to
the default setting.
spanning-tree mode {mst | pvst}
no spanning-tree mode
Syntax Description
Defaults The default mode is PVST.
Command Modes Global configuration
Command History
Usage Guidelines You cannot run both PVST and MST at the same time.
Caution Changing spanning-tree modes can disrupt traffic because all spanning-tree instances are stopped for
the previous mode and restarted in the new mode.
Examples This example shows to enable MST on the switch:
Switch(config)# spanning-tree mode mst
You can verify your setting by entering the show running-config privileged EXEC command.
Related Commands
mst Enable MST. This keyword is available only if your switch is running the enhanced
software image (EI).
pvst Enable PVST.
Release Modification
12.1(9)EA1 This command was first introduced.
Command Description
show running-config Displays the current operating configuration. For syntax information,
select Cisco IOS Configuration Fundamentals Command Reference for
Release 12.1 > Cisco IOS File Management Commands > Configuration
File Commands.