Scenario 4: Traditional STP

This scenario exercises your ability to think through the Spanning Tree Protocol operation. You are presented with a simple network of two switches. This keeps the STP complexity to a minimum while forcing you to think through the STP convergence process on a live network. Given the network diagram shown in Figure 19-4, complete the following exercises.

Figure 19-4. Network Diagram for Scenario 4

1.	Manually compute the spanning-tree topology. Note which switch is the root bridge, which ports are root ports and designated ports, and which ports are in the Blocking state.
2.	If the 100-Mbps link (port FastEthernet 1/2) is disconnected, what happens with the STP?
3.	If the 1000-Mbps link (port GigabitEthernet 2/1) is disconnected, how much time will elapse before the two switches can communicate again? (Assume that both switches use the default STP timer values and no additional features for faster convergence.)
4.	Assume that the physical 1000-Mbps link (port GigabitEthernet 2/1) stays up and active, but BPDUs are not allowed to pass (that is, an access list filter is blocking BPDUs). What happens and when?