Hello, we have switched over to almost all HP Aruba CX series switches which are running MSTP by default with the Core Switch set as the root. We have a couple Cisco 3850 switches we cannot replace due to budget. I would like these to run MSTP instead of Rapid-STP for consistency and we're seeing numerous topology changes, which we think is due to running both.
I have tried the commands below on the Cisco. It comes back online after the changing it to MSTP but reports the root switch as itself. Is there something I'm missing to do this properly or is this correct and expected behavior?
Cisco config:
config t
spanning-tree mst configuration
instance 0 vlan 1-4094
name 88:25:10:e9:a6:00
revision 0
show pending
exit
spanning-tree mode mst
end
show spanning-tree
MST0
Spanning tree enabled protocol mstp
Root ID Priority 32768
Address 0c97.5f4c.2200
Cost 20000
Port 1 (GigabitEthernet1/0/1)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32768 (priority 32768 sys-id-ext 0)
Address 8890.8dde.e980
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
show spanning-tree mst
##### MST0 vlans mapped: 1-4094
Bridge address 8890.8dde.e980 priority 32768 (32768 sysid 0)
Root address 0c97.5f4c.2200 priority 32768 (32768 sysid 0)
port Gi1/0/1 path cost 20000
Regional Root this switch
Operational hello time 2 , forward delay 15, max age 20, txholdcount 6
Configured hello time 2 , forward delay 15, max age 20, max hops 20
Aruba config output from core switch:
show spanning-tree mst-config
MST configuration information
MST config ID : 88:25:10:e9:a6:00
MST config revision : 0
MST config digest : AC36177F50283CD4B83821D8AB26DE62
Number of instances : 0
Instance ID Member VLANs
--------------- ----------------------------------
0 1-4094
show span
Spanning tree status : Enabled Protocol: MSTP
MST0
Root ID Priority : 0
MAC-Address: 88:25:10:e9:a6:00
This bridge is the root
Hello time(in seconds):2 Max Age(in seconds):20
Forward Delay(in seconds):15
Bridge ID Priority : 0
MAC-Address: 88:25:10:e9:a6:00
Hello time(in seconds):2 Max Age(in seconds):20
Forward Delay(in seconds):15