Lab 3.2.4 Verifying STP with Show Commands

Step 1: Cable the network 

What is the advantage of providing redundant links in a network like this one?

Step 2: Configure the switches

Step 3: Configure the hosts

Step 4: Verify connectivity

To verify that the network is set up successfully, ping from Host 1 to Host 2. Was the ping successful?

Step 5: Examine interface VLAN 1 information

a. On SwitchA, enter the command show interface vlan1 at the privileged EXEC mode prompt. What is the MAC address of SwitchA?

b. On SwitchB, enter the command show interface vlan1 at the privileged EXEC mode prompt. What is the MAC address of SwitchB? Which switch should be the root of the spanning tree for this network?

Step 6: Determine the roles of ports participating in the spanning tree on each switch

On SwitchB, enter the command show spanning-tree at the privileged EXEC mode prompt. Which switch is the root bridge? The spanning tree is using three ports on each switch. Complete this chart indicating the port state and role for each port.

Step 7: Create a change in the network topology

a. Remove the crossover cable from the forwarding port on the non-root bridge.

b. Wait a few seconds, and then enter the show spanning-tree command again on the non-root bridge. What changes do you see in the spanning tree?

c. Check the spanning tree on the root bridge.

What changes have occurred there?

d. Continue to check the spanning tree on both switches until a new tree has been calculated and all ports are either forwarding or blocking. How long does it take for this to happen?

e. Replace the cable that was removed in Step 7a.

f. Wait again until both switches have recalculated their tables. How much time has passed since you first removed the crossover cable?

g. What effect did these topology changes have on network uptime?

Step 8: Examine the spanning tree on each switch

a. On each switch, enter the command show spanning-tree detail.

b. Examine the information for port Fa0/1. The output shows the interface, role, and state for each switch. It also provides details about port activity and characteristics.

How might the following information help you to verify the status of the network and troubleshoot network problems?

1)      Number of transitions to forwarding state:

2)      Number of BPDUs that have been sent and received:

c. On each switch, enter the following commands. Determine the type of information that each command provides: show spanning-tree bridge jawab: show spanning-tree summary

Step 9: Reflection

Your networking team is deciding whether to disable Spanning Tree Protocol on the switches in your corporate network. Explain how you would feel about this decision. What are the advantages and disadvantages? How would this decision affect your network design?