Spanning-Tree Mode - Cisco Catalyst 2950 Command Reference Manual

Chapter 2 Catalyst 2950 and 2955 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
mst
pvst
rapid-pvst
Defaults The default mode is PVST+.
Command Modes Global configuration
Command History Release
12.1(9)EA1
12.1(13)EA1
12.1(20)EA2
Usage Guidelines
The switch supports PVST+, rapid PVST+, and MSTP, but only one version can be active at any time.
All VLANs run PVST+, all VLANs run rapid PVST+, or all VLANs run MSTP.
Changing spanning-tree modes can disrupt traffic because all spanning-tree instances are stopped for the
Caution
previous mode and restarted in the new mode.
When you enable the MST mode, RSTP is automatically enabled.
Examples 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.
0L-10102-01
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.
This command was added to the standard software image (SI).
Catalyst 2950 and Catalyst 2955 Switch Command Reference
spanning-tree mode
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