Spanning-Tree Mst Pre-Standard - Cisco Catalyst 3750-X Command Reference Manual

Cisco ios release 15.2(1)e and later

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Table of Contents

Chapter 2 Catalyst 3750-X and 3560-X Switch Cisco IOS Commands

spanning-tree mst pre-standard

Use the spanning-tree mst pre-standard interface configuration command to configure a port to send

only prestandard bridge protocol data units (BPDUs).

Syntax Description

This command has no arguments or keywords.

Command Default

The default state is automatic detection of prestandard neighbors.

Command Modes

Interface configuration

Command History

Usage Guidelines

The port can accept both prestandard and standard BPDUs. If the neighbor types are mismatched, only

the common and internal spanning tree (CIST) runs on this interface.

If a switch port is connected to a switch running prestandard Cisco IOS software, you must use the

spanning-tree mst pre-standard interface configuration command on the port. If you do not configure

the port to send only prestandard BPDUs, the Multiple STP (MSTP) performance might diminish.

When the port is configured to automatically detect prestandard neighbors, the prestandard flag always

appears in the show spanning-tree mst commands.

This example shows how to configure a port to send only prestandard BPDUs:

Switch(config-if)# spanning-tree mst pre-standard

You can verify your settings by entering the show spanning-tree mst privileged EXEC command.

Related Commands

show spanning-tree

spanning-tree mst pre-standard

no spanning-tree mst pre-standard

Modification

This command was introduced.

mst instance-id

Displays multiple spanning-tree (MST) information,

including the prestandard flag, for the specified interface.

Catalyst 3750-X and 3560-X Switch Command Reference

spanning-tree mst pre-standard

Catalyst 3560-x