Reference Guide

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
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
!
protocol spanning-tree mstp
no disable
Dell#
Adding and Removing Interfaces
To add and remove interfaces, use the following commands.
To add an interface to the MSTP topology, configure it for Layer 2 and add it to a VLAN.
If you previously disabled MSTP on the interface using the no spanning-tree 0 command, to enable MSTP, use the
following command.
● spanning-tree 0
To remove an interface from the MSTP topology, use the no spanning-tree 0 command.
Creating Multiple Spanning Tree Instances
To create multiple spanning tree instances, use the following command.
A single MSTI provides no more benefit than RSTP. To take full advantage of MSTP, create multiple MSTIs and map VLANs to
them.
● Create an MSTI.
PROTOCOL MSTP mode
msti
Specify the keyword vlan then the VLANs that you want to participate in the MSTI.
The following example shows using the msti command.
Dell(conf)#protocol spanning-tree mstp
Dell(conf-mstp)#msti 1 vlan 100
Dell(conf-mstp)#msti 2 vlan 200-300
Dell(conf-mstp)#show config
!
protocol spanning-tree mstp
no disable
MSTI 1 VLAN 100
MSTI 2 VLAN 200-300
502
Multiple Spanning Tree Protocol (MSTP)