Concept Guide

Command Modes SPANNING TREE
Command History
This guide is platform-specic. For command information about other platforms, see the relevant Dell EMC
Networking OS Command Line Reference Guide.
Version Description
9.13(0.1) Introduced on MXL, FN IOM, S6000, S3100, S4810, S4820T, S3048–ON, S4048–ON,
S4048T-ON, S6000–ON, S6010–ON, S6100–ON, S5048F-ON, C9010, and Z9100–ON,
Usage Information
This command is used to keep the port-channel path cost constant regardless of the operational status of the
port-channel member ports.
This command is supported in all STP modes such as STP, RSTP, MSTP, and PVST.
The command behavior does not change when a new member port is added to the port-channel or an existing
member port is deleted from the conguration. The path cost reects the cumulative speed of the port-channel
member ports.
Example
DELLEMC(conf)#protocol spanning-tree pvst
DELLEMC(conf-pvst)#port-channel path-cost custom
protocol spanning-tree mstp
To enable and congure the multiple spanning tree group, enter MULTIPLE SPANNING TREE mode.
Syntax
protocol spanning-tree mstp
To disable the multiple spanning tree group, use the no protocol spanning-tree mstp command.
Defaults Not congured.
Command Modes CONFIGURATION
Supported Modes Full–Switch
Command History
Version Description
9.9(0.0) Introduced on the FN IOM.
8.3.16.1 Introduced on the MXL 10/40GbE Switch IO Module.
Usage Information
MSTP is not enabled when you enter MULTIPLE SPANNING TREE mode. To enable MSTP globally on the switch,
enter the no disable command while in MULTIPLE SPANNING TREE mode.
For more information about the multiple spanning tree protocol, refer to the Dell Networking OS Conguration
Guide.
Example
Dell(conf)#protocol spanning-tree mstp
Dell(config-mstp)#no disable
Related Commands disable — disables multiple spanning tree.
886 Multiple Spanning Tree Protocol (MSTP)