Administrator 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.
DellEMC(conf)#protocol spanning-tree mstp
DellEMC(config-mstp)#show config
!
protocol spanning-tree mstp
no disable
DellEMC#
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 examples shows the msti command.
DellEMC(conf)#protocol spanning-tree mstp
DellEMC(conf-mstp)#msti 1 vlan 100
DellEMC(conf-mstp)#msti 2 vlan 200-300
DellEMC(conf-mstp)#show config
!
protocol spanning-tree mstp
no disable
MSTI 1 VLAN 100
MSTI 2 VLAN 200-300
All bridges in the MSTP region must have the same VLAN-to-instance mapping.
Multiple Spanning Tree Protocol (MSTP)
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