Reference Guide

Configure Multiple Spanning Tree Protocol
Configuring multiple spanning tree is a four-step process.
1. Configure interfaces for Layer 2.
2. Place the interfaces in VLANs.
3. Enable the multiple spanning tree protocol.
4. Create multiple spanning tree instances and map VLANs to them.
Related Configuration Tasks
The following are the related configuration tasks for MSTP.
• Creating Multiple Spanning Tree Instances
• Adding and Removing Interfaces
• Influencing MSTP Root Selection
• Interoperate with Non-Dell Networking OS Bridges
• Modifying Global Parameters
• Modifying the Interface Parameters
• Configuring an EdgePort
• Flush MAC Addresses after a Topology Change
• Debugging and Verifying MSTP Configurations
• Prevent Network Disruptions with BPDU Guard
• Enabling SNMP Traps for Root Elections and Topology Changes
• Configuring Spanning Trees as Hitless
Enable Multiple Spanning Tree Globally
MSTP is not enabled by default. To enable MSTP globally, use the following commands.
When you enable MSTP, all physical, VLAN, and port-channel interfaces that are enabled and in Layer 2
mode are automatically part of the MSTI 0.
• Within an MSTI, only one path from any bridge to any other bridge is enabled.
• Bridges block a redundant path by disabling one of the link ports.
1. Enter PROTOCOL MSTP mode.
CONFIGURATION mode
protocol spanning-tree mstp
2. Enable MSTP.
PROTOCOL MSTP mode
no disable
Example of Verifying that MSTP is Enabled
To verify that MSTP is enabled, use the show config command in PROTOCOL MSTP mode.
Dell(conf)#protocol spanning-tree mstp
Dell(config-mstp)#show config
Multiple Spanning Tree Protocol (MSTP)
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