CCNA LAB Practice - Verification Of Spanning Tree Operation in PVST Mode

Verification Of Spanning Tree Operation in PVST Mode

Since, it is known that Cisco catalyst switches are running in PVST mode, by-default. It means that each spanning tree instance is used for each VLAN. The Root Switch can be different for every VLAN.

Diagram

Procedure

1. Make a VLAN 5 on both switches.
2. Set the spanning tree priority on 2950-SWB switch to become a Root Switch for VLAN 5. Otherwise, the default Root of VLAN 5 will be 2950-SWA.
3. Verified the results on 2950-SWA.
4. Verified the results on 2950-SWB.

Configuration

Step 1: Make a VLAN 5 on both switches.

2950-SWB(config)#vlan 5

2950-SWB(config-vlan)#name vlan-5

Note:- Commands will be same on 2950-SWA switch.

Step 2: Set the spanning tree priority on 2950-SWB switch to become a Root

                 Switch for VLAN 5. Otherwise, the default Root of VLAN 5 will be 2950-

                 SWA.

2950-SWB(config)#spanning-tree vlan 5 priority 28672

Step 3(A): Verified By Show command on 2950-SWB Switch for VLAN 1.

2950-SWB# sh spanning-tree vlan 1

VLAN0001

  Spanning tree enabled protocol ieee

  Root ID        Priority            32769

                        Address          000b.5f03.f9c0

                        Cost                19

                        Port                 23 (FastEthernet0/23)

                        Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID     Priority            32769  (priority 32768 sys-id-ext 1)

                        Address          000f.2468.0500

                        Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

                        Aging Time 300

Interface           Role     Sts       Cost                 Prio.     Nbr Type

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

Fa0/1               Desg    FWD   19                    128.1     Edge P2p

Fa0/23             Root    FWD   19                    128.23   P2p

Fa0/24             Altn     BLK    19                    128.24   P2p

Step 3(B): Verified By Show command on 2950-SWB Switch for VLAN 5.

2950-SWB# sh spanning-tree vlan 5

VLAN0005

  Spanning tree enabled protocol ieee

  Root ID        Priority    28677

                        Address     000f.2468.0500

                        This bridge is the root

                        Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID     Priority    28677  (priority 28672 sys-id-ext 5)

                        Address     000f.2468.0500

                        Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

                        Aging Time 300

Interface           Role     Sts       Cost                 Prio.     Nbr Type

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

Fa0/23             Desg   FWD   19                    128.23   P2p

Fa0/24             Desg   FWD   19                    128.24   P2p

Step 4(A): Verified By Show command on 2950-SWA Switch for VLAN 1.

2950-SWA#sh spanning-tree vlan 1

VLAN0001

  Spanning tree enabled protocol ieee

  Root ID        Priority            32769

                        Address          000b.5f03.f9c0

                        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          000b.5f03.f9c0

                        Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

                        Aging Time 300

Interface           Role     Sts       Cost                 Prio.                 Nbr Type

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

Fa0/1               Desg    FWD   19                    128.1               P2p

Fa0/23             Desg   FWD   19                    128.23             P2p

Fa0/24             Desg   FWD   19                    128.24             P2p

Step 4(B): Verified By Show command on 2950-SWB Switch for VLAN 5.

2950-SWA#sh spanning-tree vlan 5

VLAN0005

  Spanning tree enabled protocol ieee

  Root ID        Priority            28677

                        Address          000f.2468.0500

                        Cost                19

                        Port                 23 (FastEthernet0/23)

                        Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID     Priority            32773  (priority 32768 sys-id-ext 5)

                        Address          000b.5f03.f9c0

                        Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

                        Aging Time 300

Interface           Role     Sts       Cost                 Prio.                 Nbr Type

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

Fa0/23             Root    FWD   19                    128.23             P2p

Fa0/24             Altn     BLK    19                    128.24             P2p