Spanning-Tree Blocking Vlan

[heheho]

Hello, I'm facing issue to block all the VLANS in Port g0/2 for Switch1. I changed the root primary for each VLAN then i got to block those, but VLAN 56 cannot be blocked. I tried changing the cost, the priority still not blocking VLAN 56. I am not sure which part I have done wrong.  🥺

SWITCH>EN

SWITCH#SH SPAN INT G0/1

VLAN ROLE STS COST PRIO.NBR TYPE

---------------- ---- --- --------- -------- --------------------------------

VLAN0001 ROOT FWD 4 128.25 P2P

VLAN0002 ROOT FWD 4 128.25 P2P

VLAN0003 ROOT FWD 4 128.25 P2P

VLAN0004 ROOT FWD 4 128.25 P2P

VLAN0005 ROOT FWD 4 128.25 P2P

VLAN0006 ROOT FWD 4 128.25 P2P

VLAN0016 ROOT FWD 4 128.25 P2P

VLAN0025 ROOT FWD 4 128.25 P2P

VLAN0035 ROOT FWD 4 128.25 P2P

VLAN0046 ROOT FWD 4 128.25 P2P

VLAN0056 DESG FWD 4 128.25 P2P

SWITCH#SH SPAN INT G0/2

VLAN ROLE STS COST PRIO.NBR TYPE

---------------- ---- --- --------- -------- --------------------------------

VLAN0001 ALTN BLK 4 128.26 P2P

VLAN0002 ALTN BLK 10000000 128.26 P2P

VLAN0003 ALTN BLK 4 128.26 P2P

VLAN0004 ALTN BLK 4 128.26 P2P

VLAN0005 ALTN BLK 4 128.26 P2P

VLAN0006 ALTN BLK 4 128.26 P2P

VLAN0016 ALTN BLK 4 128.26 P2P

VLAN0025 ALTN BLK 4 128.26 P2P

VLAN0035 ALTN BLK 4 128.26 P2P

VLAN0046 ALTN BLK 4 128.26 P2P

VLAN0056 DESG FWD 50000000 128.26 P2P

[liviu.gheorghe · Accepted solution]

After looking at the requirements and the topology, I think it's oversight of the instructions and requirements for this lab exercise. The requirement is to create the vlan 56 in the top switch, but not in the bottom switch. In this situation ports Gi0/1 and Gi0/2 on the top switch will never be in blocking for vlan 56 because the ports don't need to be - there is no loop in the topology for vlan 56.

One way to satisfy the requirement is to create vlan 56 on the bottom switch and make the bottom switch the root of the spanning tree with the command spanning-tree vlan 1-56 root primary .

This way all thee vlans will be in blocking on switch top for port gi0/2.

HTH

[heheho]

Can the VLAN56 be blocked in int g0/2? So it will only use int g0/1?

[MHM Cisco World]

Can you draw topology 

MHM

[heheho]

.

[MHM Cisco World]

Sorry maybe help you, I have bad experience in PKT. 

MHM

[heheho]

no worries!!!!!!