CCNA LAB Practice - Spanning Tree Protocol On 2950 Switch

Spanning Tree Protocol

On

2950 Switch                      

Objective

Understanding the Spanning tree protocol operation in switched environment by creating a multiple or redundant link between switches.

Diagram With Redundant Link

Procedure

1. Verifying the Spanning Tree Protocol on the 2950-SWA switch.
2. Verifying the Spanning Tree Protocol on the 2950-SWB switch.
3. Select Root Port By Changing Cost Of Ports On 2950-SWB (Non-Root Switch).
4. Verifying the results by changing cost on 2950-SWB.
5. Select Root Port By Changing Priority Of Ports On 2950-SWA (Root Switch).
6. Verifying the results by changing Priority of ports on 2950-SWA & 2950-SWB.

Configuration         

Step 1(A): Verifying the Spanning Tree Protocol on the 2950-SWA switch.

2950-SWA#show spanning-tree

OR

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 1(B): Verifying the detailed information of Spanning Tree Protocol on the

                         2950-SWA switch.

2950-SWA#show spanning-tree detail

OR

2950-SWA#sh spanning-tree vlan 1 detail

 VLAN0001 is executing the ieee compatible Spanning Tree protocol

  Bridge Identifier has priority 32768, sysid 1, address 000b.5f03.f9c0

  Configured hello time 2, max age 20, forward delay 15

  We are the root of the spanning tree

  Topology change flag not set, detected flag not set

  Number of topology changes 4 last change occurred 00:05:35 ago

          from FastEthernet0/23

  Times:  hold 1, topology change 35, notification 2

          hello 2, max age 20, forward delay 15

  Timers: hello 1, topology change 0, notification 0, aging 300

 Port 1 (FastEthernet0/1) of VLAN0001 is forwarding

   Port path cost 19, Port priority 128, Port Identifier 128.1.

   Designated root has priority 32769, address 000b.5f03.f9c0

   Designated bridge has priority 32769, address 000b.5f03.f9c0

   Designated port id is 128.1, designated path cost 0

   Timers: message age 0, forward delay 0, hold 0

   Number of transitions to forwarding state: 1

   Link type is point-to-point by default

   BPDU: sent 1657, received 0

 Port 23 (FastEthernet0/23) of VLAN0001 is forwarding

   Port path cost 19, Port priority 128, Port Identifier 128.23.

   Designated root has priority 32769, address 000b.5f03.f9c0

   Designated bridge has priority 32769, address 000b.5f03.f9c0

   Designated port id is 128.23, designated path cost 0

   Timers: message age 0, forward delay 0, hold 0

   Number of transitions to forwarding state: 1

   Link type is point-to-point by default

   BPDU: sent 170, received 2

 Port 24 (FastEthernet0/24) of VLAN0001 is forwarding

   Port path cost 19, Port priority 128, Port Identifier 128.24.

   Designated root has priority 32769, address 000b.5f03.f9c0

   Designated bridge has priority 32769, address 000b.5f03.f9c0

   Designated port id is 128.24, designated path cost 0

   Timers: message age 0, forward delay 0, hold 0

   Number of transitions to forwarding state: 1

   Link type is point-to-point by default

   BPDU: sent 1643, received 3

Step 2(A): Verifying the Spanning Tree Protocol on the 2950-SWB switch.

2950-SWB#show spanning-tree

OR

2950-SWB#show 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               P2p

Fa0/23             Root                FWD    19      128.23             P2p

Fa0/24             Altn                 BLK     19       128.24             P2p

Step 2(B): Verifying the detailed information of Spanning Tree Protocol on the

                         2950-SWB switch.

2950-SWB#show spanning-tree detail

                     

OR

2950-SWB#sh spanning-tree vlan 1 detail

 VLAN0001 is executing the ieee compatible Spanning Tree protocol

  Bridge Identifier has priority 32768, sysid 1, address 000f.2468.0500

  Configured hello time 2, max age 20, forward delay 15

  Current root has priority 32769, address 000b.5f03.f9c0

  Root port is 23 (FastEthernet0/23), cost of root path is 19

  Topology change flag not set, detected flag not set

  Number of topology changes 7 last change occurred 00:13:53 ago

          from FastEthernet0/23

  Times:  hold 1, topology change 35, notification 2

          hello 2, max age 20, forward delay 15

  Timers: hello 0, topology change 0, notification 0, aging 300

 Port 1 (FastEthernet0/1) of VLAN0001 is forwarding

   Port path cost 19, Port priority 128, Port Identifier 128.1.

   Designated root has priority 32769, address 000b.5f03.f9c0

   Designated bridge has priority 32769, address 000f.2468.0500

   Designated port id is 128.1, designated path cost 19

   Timers: message age 0, forward delay 0, hold 0

   Number of transitions to forwarding state: 1

   Link type is point-to-point by default

   BPDU: sent 1910, received 0

 Port 23 (FastEthernet0/23) of VLAN0001 is forwarding

   Port path cost 19, Port priority 128, Port Identifier 128.23.

   Designated root has priority 32769, address 000b.5f03.f9c0

   Designated bridge has priority 32769, address 000b.5f03.f9c0

   Designated port id is 128.23, designated path cost 0

   Timers: message age 1, forward delay 0, hold 0

   Number of transitions to forwarding state: 1

   Link type is point-to-point by default

   BPDU: sent 2, received 433

 Port 24 (FastEthernet0/24) of VLAN0001 is blocking

   Port path cost 19, Port priority 128, Port Identifier 128.24.

   Designated root has priority 32769, address 000b.5f03.f9c0

   Designated bridge has priority 32769, address 000b.5f03.f9c0

   Designated port id is 128.24, designated path cost 0

   Timers: message age 2, forward delay 0, hold 0

   Number of transitions to forwarding state: 2

   Link type is point-to-point by default

   BPDU: sent 3, received 1906

Step 3: Select Root Port By Changing Cost Of Ports On 2950-SWB (Non-Root

                 Switch).

                               

2950-SWB(config)#int fastEthernet 0/24

2950-SWB(config-if)#spanning-tree vlan 1 cost 18

Step 4: Verifying the results by changing cost on 2950-SWB (Non-Root Switch).

2950-SWB#sh spanning-tree

OR

2950-SWB#sh spanning-tree vlan 1

VLAN0001

  Spanning tree enabled protocol ieee

  Root ID        Priority            32769

                        Address          000b.5f03.f9c0

                        Cost                18

                        Port                 24 (FastEthernet0/24)

                        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          P2p

Fa0/23             Altn     BLK                19      128.23        P2p

Fa0/24             Root    FWD               18      128.24        P2p

Step 5: Select Root Port By Changing Priority Of Ports On Root Switch

2950-SWA(config)#int fastEthernet 0/24

2950-SWA(config-if)#spanning-tree vlan 1 port-priority 112

Step 6(A): Verifying the results by changing Priority Of Ports On 2950-SWA

                        (Root Switch).

Note: After 50 sec’s, the port will be forwarded after taking part into election.

2950-SWA#sh spanning-tree

OR

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      112.24        P2p

Step 6(B): Verifying the results by changing Priority Of Ports On 2950-SWB

                        (Non-Root Switch).

2950-SWB#sh spanning-tree

OR

2950-SWB#sh spanning-tree vlan 1

VLAN0001

  Spanning tree enabled protocol ieee

  Root ID        Priority            32769

                        Address          000b.5f03.f9c0

                        Cost                19

                        Port                 24 (FastEthernet0/24)

                        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          P2p

Fa0/23             Altn     BLK                19      128.23        P2p

Fa0/24             Root    FWD               19      128.24        P2p