Enabling MSTP on a VLAN

Procedure

Enter configuration mode.
```
device# configure terminal
```
Enter the protocol command to enable MSTP configuration.
```
device(config)# protocol spanning-tree mstp
```

Map a VLAN to an MSTP instance.

device(config-mstp)# instance 5 vlan 300

Return to privileged EXEC mode.
```
device(config-mstp)# end
```

Verify the configuration.

device# show spanning-tree mst

 Spanning-tree Mode: Multiple Spanning Tree Protocol

 CIST Root Id: 8000.609c.9f5d.4800 (self)
 CIST Bridge Id: 8000.609c.9f5d.4800
 CIST Reg Root Id: 8000.609c.9f5d.4800 (self)

 CIST Root Forward Delay: 15; Hello Time: 2; Max Age: 20; Max-hops: 20
 Configured Forward Delay: 15; Hello Time: 2; Max Age: 20; Max-hops: 20;
 Tx-HoldCount: 6
 Number of topology change(s): 0

 Bpdu-guard errdisable timeout: disabled
 Bpdu-guard errdisable timeout interval: 300 sec
 Migrate Time: 3 sec

  Name           : NULL
  Revision Level : 0
  Digest         : 0xD5FF4C3F6C18E2F27AF3A8300297ABAA

  Instance        VLAN
  --------        ----
   0:             1
   5:             100

Observe that the settings comply with the formula set out in the STP parameters section, as:

(2 × (forward delay - 1)) ≥ maximum age ≥ (2 × (hello time + 1))

or in this case: 28 ≥ 20 ≥ 6.

Save the configuration.

device# copy running-config startup-config

Enable spanning tree on a VLAN configuration example

device# configure terminal
device(config)# protocol spanning-tree mstp
device(config-mstp)# instance 5 vlan 300
device(config-mstp)# end
device# show spanning-tree mst
device# copy running-config startup-config