I am running MST on my network with 1 instance right now but will soon be 2. If I issue the show spanning-tree command here is what I see:
MIB-SW-CORE-01#show spanning-tree
MST0
Spanning tree enabled protocol mstp
Root ID Priority 32768
Address 000d.2908.3b80
Cost 0
Port 3 (GigabitEthernet0/3)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32768 (priority 32768 sys-id-ext 0)
Address 000f.23c1.d100
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi0/1 Desg FWD 20000 128.1 P2p
Gi0/2 Desg FWD 20000 128.2 P2p
Gi0/3 Root FWD 20000 128.3 P2p Pre-STD-Rx
Gi0/4 Desg FWD 20000 128.4 P2p
Gi0/11 Desg FWD 200000 128.11 P2p Edge
Gi0/12 Desg FWD 200000 128.12 P2p Edge
MST1
Spanning tree enabled protocol mstp
Root ID Priority 32769
Address 000d.2908.3b80
Cost 20000
Port 3 (GigabitEthernet0/3)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32769 (priority 32768 sys-id-ext 1)
Address 000f.23c1.d100
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi0/1 Desg FWD 20000 128.1 P2p
Gi0/2 Desg FWD 20000 128.2 P2p
Gi0/3 Root FWD 20000 128.3 P2p Pre-STD-Rx
Gi0/4 Desg FWD 20000 128.4 P2p
Gi0/11 Desg FWD 200000 128.11 P2p Edge
Gi0/12 Desg FWD 200000 128.12 P2p Edge
Is there a reason that my CORE switch is not showing up as the root even through I have the following?
spanning-tree mode mst
spanning-tree logging
spanning-tree portfast bpduguard default
spanning-tree extend system-id
!
spanning-tree mst configuration
name mib-mstp
revision 1
instance 1 vlan 1, 8, 13-14, 17, 151-152
!
spanning-tree vlan 1,8,13-14,17,151-152 priority 8192
