Switch SW1 connects via a cable to switch SW2’s G0/1 port. Which of the following conditions is the most likely to cause SW1’s late collision counter to continue to increment?

Switch SW1 connects via a cable to switch SW2’s G0/1 port. Which of the following conditions is the most likely to cause SW1’s late collision counter to continue to increment?

• SW2’s G0/1 has been configured with a shutdown interface subcommand.
• The two switches have been configured with different values on the speed interface subcommand.
• A duplex mismatch exists with SW1 set to full duplex.
• A duplex mismatch exists with SW1 set to half duplex.

Explanation: For the two answers about a duplex mismatch, that condition does cause collisions, particularly late collisions, but only the side using CSMA/CD logic (the half-duplex side) has any concept of collisions. So, if switch SW1 was using half duplex, and switch SW2 using full duplex, SW1 would likely see late collisions and see that counter increment over time.
If switch SW2 had shut down its interface, switch SW1’s interface would be in a down/down state, and none of the counters would increment. Also, if both switch ports had been configured with different speeds, again the ports would be in a down/down state, and none of the interface counters would increment.