spanning-tree mst simulate pvst global

To prevent the Multiple Spanning Tree (MST) switch from automatically interoperating with a connecting device running Rapid per VLAN Spanning Tree Plus (Rapid PVST+), use the spanning-tree mst simulate pvst global command. To return to the default settings, which is a seamless operation between MST and Rapid PVST+ on the switch, use the no spanning-tree mst simulate pvst global command.

spanning-tree mst simulate pvst global

no spanning-tree mst simulate pvst global

Syntax Description

This command has no keywords or arguments.

Command Default

Enabled. By default, the switch interoperates seamlessly between MST and Rapid PVST+.

Command Modes

Global configuration mode

Command History

Release
Modification

4.0(0)N1(1a)

This command was introduced.


Usage Guidelines

MST does not require user configuration to interoperate with Rapid PVST+. The PVST+ simulation feature enables this seamless interoperability. However, you may want to control the connection between MST and Rapid PVST+ to protect against accidentally connecting an MST-enabled port to a Rapid PVST+-enabled port.

When you use the no spanning-tree mst simulate pvst global command, the switch running in MST mode moves all interfaces that receive a Rapid PVST+ (SSTP) bridge protocol data unit (BPDU) into the Spanning Tree Protocol (STP) blocking state. Those interfaces remain in the inconsistent state until the port stops receiving Rapid PVST+ BPDUs, and then the port resumes the normal STP transition process.

You can also use this command from the interface mode, and the configuration applies to the entire switch.


Note To block automatic MST and Rapid PVST+ interoperability for specific interfaces, see the spanning-tree mst simulate pvst command.


This command is useful when you want to prevent accidental connection with a device not running MST.

To return the switch to seamless operation between MST and Rapid PVST+, use the spanning-tree mst simulate pvst global command.

Examples

This example shows how to prevent all ports on the switch from automatically interoperating with a connected device running Rapid PVST+:

switch(config)# no spanning-tree mst simulate pvst global  

Related Commands

Command
Description

spanning-tree mst simulate pvst

Enables seamless interoperation between MST and Rapid PVST+ by the interface.