Administrator Guide
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.
Example of the msti Command
Example of Viewing MSTP Port States
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
All bridges in the MSTP region must have the same VLAN-to-instance mapping.
To view which instance a VLAN is mapped to, use the show spanning-tree mst vlan command from
EXEC Privilege mode.
To view the forwarding/discarding state of the ports participating in an MSTI, use the show spanning-tree
msti command from EXEC Privilege mode.
Dell#show spanning-tree msti 1
MSTI 1 VLANs mapped 100
Root Identifier has priority 32768, Address 0001.e806.953e
Root Bridge hello time 2, max age 20, forward delay 15, max hops 19
Bridge Identifier has priority 32768, Address 0001.e80d.b6d6
Configured hello time 2, max age 20, forward delay 15, max hops 20
Current root has priority 32768, Address 0001.e806.953e
Number of topology changes 2, last change occured 1d2h ago on TenGig 1/21
Port 374 (TenGigabitEthernet 1/21) is root Forwarding
Port path cost 2000, Port priority 128, Port Identifier 128.374
Designated root has priority 32768, address 0001.e806.953e
Designated bridge has priority 32768, address 0001.e806.953e
Designated port id is 128.374, designated path cost 2000
Number of transitions to forwarding state 1
BPDU (MRecords): sent 93671, received 46843
The port isnot in the Edge port mode, bpdu filter is disabled
Port 384 (TenGigabitEthernet 1/31) is alternate Discarding
Port path cost 2000, Port priority 128, Port Identifier 128.384
Designated root has priority 32768, address 0001.e806.953e
Designated bridge has priority 32768, address 0001.e809.c24a
Multiple Spanning Tree Protocol (MSTP) 607