Question 110
Switches on one Rapid PVST+ VLAN instance advertise these bridge IDs: SW-1 (priority 16384, MAC 7c7be5e59e30); SW-2 (priority 32768, MAC 3774c0893e9c); SW-3 (priority 12288, MAC 586873313aab); SW-4 (priority 20480, MAC 14ca4b5bc9b5). They are powered on with no previous root. Which switch is the elected root?
Explanation
Correct Answer
The STP root is the switch with the numerically lowest bridge ID: priority is compared first, followed by MAC on ties. SW-3 has the lowest priority 12288.
Incorrect Answers
Its advertised priority is greater than the winner 12288, and no tie breaker changes the result.
That explanation does not distinguish this option. “SW-4 (priority 20480, MAC 14ca4b5bc9b5)” is an alternative action, but it does not by itself establish the outcome required in this case.
That explanation does not distinguish this option. “SW-1 (priority 16384, MAC 7c7be5e59e30)” is an alternative action, but it does not by itself establish the outcome required in this case.