CML Lab -Two Switches claim ot be the root of spanning tree

[Eriknx]

Hello
I suspect that there is some kind of a problem with CML. What do you think why is this happening ?

There is no VTP and only VLAN 1. When I shut the lab down yesterday, everything was working as expected.
It was IOSvL2-3-Root 
IOSvL2-3-3 was blocking on G0/2, G0/1 was his root port.
Now, IOSvL2-3-3 is root for everybody except the planned root IOSvl2-3
========================================

2-3-2#sh spann

VLAN0001
Spanning tree enabled protocol ieee
Root ID Priority 32769
Address 5254.000a.7ad7
Cost 4
Port 3 (GigabitEthernet0/2)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 32769 (priority 32768 sys-id-ext 1)
Address 5254.000e.f6aa
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi0/1 Desg FWD 4 128.2 P2p
Gi0/2 Root FWD 4 128.3 P2p

(config-if-range)#do sh spann

VLAN0001
Spanning tree enabled protocol ieee
Root ID Priority 32769
Address 5254.000a.7ad7
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 32769 (priority 32768 sys-id-ext 1)
Address 5254.000a.7ad7
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi0/1 Desg FWD 5 128.2 P2p
Gi0/2 Desg FWD 4 128.3 P2p

==========================================

Root#sh spann

VLAN0001
Spanning tree enabled protocol ieee
Root ID Priority 1
Address 5254.000c.1e1d
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 1 (priority 0 sys-id-ext 1)
Address 5254.000c.1e1d
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 15 sec

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi0/0 Desg FWD 4 128.1 P2p
Gi0/1 Desg FWD 4 128.2 P2p

=================================================
Other switches see 2-3-3 as root for some reason

2-3-0#sh spann

VLAN0001
Spanning tree enabled protocol ieee
Root ID Priority 32769
Address 5254.000a.7ad7
Cost 8
Port 1 (GigabitEthernet0/0)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 32769 (priority 32768 sys-id-ext 1)
Address 5254.001f.778d
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi0/0 Root FWD 4 128.1 P2p
Gi0/1 Desg FWD 4 128.2 P2p

2-3-2#sh spann

VLAN0001
Spanning tree enabled protocol ieee
Root ID Priority 32769
Address 5254.000a.7ad7
Cost 4
Port 3 (GigabitEthernet0/2)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 32769 (priority 32768 sys-id-ext 1)
Address 5254.000e.f6aa
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi0/1 Desg FWD 4 128.2 P2p
Gi0/2 Root FWD 4 128.3 P2p

2-3-1#sh spann

VLAN0001
Spanning tree enabled protocol ieee
Root ID Priority 32769
Address 5254.000a.7ad7
Cost 4
Port 1 (GigabitEthernet0/0)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 32769 (priority 32768 sys-id-ext 1)
Address 5254.001d.199a
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi0/0 Root FWD 4 128.1 P2p
Gi0/1 Desg FWD 4 128.2 P2p

[Eriknx]

I did shut down all switches and then first powered up the Root and 2-3-0 (to the left of Root). 2-3-0 then saw recognized Root as root switch. After that, I powered up all the other switches and the topology works fine, 2-3-3 root port is G0/1 (as it should be) and it is blocking on G0/2.

I know that GNS3 is notorious for bad switching and I had a chance to experience that. That is the reason I started working with CML2. 
Does anyone know if CML2 is also problematic with L2 switching ?

[balaji.bandi · Accepted solution]

its virtual so we can not  simulate as expected as physical switch, looks like some communication issue on virtual interface, on the first output we did not see any port blocking as you metioned on the follow output.

seen this issue randomly on GNS3/ PNET also. (even in CML2)

[Eriknx]

Thank you for the prompt reply