Spanning-Tree Mode - Cisco Catalyst 3550 Command Reference Manual

Multilayer switch

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Chapter 2 Catalyst 3550 Switch Cisco IOS Commands

spanning-tree mode

Use the spanning-tree mode global configuration command to enable per-VLAN spanning-tree plus

(PVST+), rapid PVST+, or multiple spanning tree (MST) on your switch. Use the no form of this

command to return to the default setting.

Syntax Description

The default mode is PVST+.

Command Modes

Global configuration

Command History

Usage Guidelines

The switch must run all STP instances in one of these modes: PVST+, rapid PVST+, or MST. In other

words, you cannot run STP in any two modes at the same time.

When you enable the MST mode, RSTP is automatically enabled.

Changing spanning-tree modes can disrupt traffic because all spanning-tree instances are stopped for the

previous mode and restarted in the new mode.

This example shows to enable MST on the switch:

Switch(config)# spanning-tree mode mst

This example shows to enable rapid PVST+ on the switch:

Switch(config)# spanning-tree mode rapid-pvst

You can verify your setting by entering the show running-config privileged EXEC command.

spanning-tree mode {mst | pvst | rapid-pvst}

no spanning-tree mode

Enable MST and Rapid Spanning Tree Protocol (RSTP) (based on IEEE 802.1s and

IEEE 802.1w).

Enable PVST+ (based on IEEE 802.1D).

Enable rapid PVST+ (based on IEEE 802.1w).

Modification

This command was introduced.

The rapid-pvst keyword was added.

Catalyst 3550 Multilayer Switch Command Reference

spanning-tree mode

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