Root Bridge Election by Lowest MAC When Priorities Are Equal (SW4)
Refer to the exhibit. Which switch in this configuration will be elected as the root bridge? - 
Community Votes
100% of anonymous learners picked answer D. Votes are pick records left by other test-takers — they are not the verified answer.
Community Insight
When priorities are equal, the election is decided purely by the lowest MAC address — the classic reason an old switch with a small MAC can take over as root.
With identical bridge priorities across the switches, STP elects the root by the lowest MAC address. SW4's MAC (0C:0A:05:22:05:97) is the lowest of the four, so SW4 becomes the root bridge.
Picking SW3 or SW2 by reading the MACs out of order; compare byte-by-byte from the left — 0C:0A:05 is lower than 0C:0A:18 and 0C:0A:A8.
Community Discussion (4 comments)
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Expert Analysis
Why the Answer Is Correct
D (SW4) is correct. Because every switch has the same bridge priority, the root is chosen by the lowest MAC address. SW4 (0C:0A:05:22:05:97) is lower than SW3 (0C:0A:18:81:B3:19), SW2 (0C:0A:A8:1A:3C:9D), and SW1 (0C:4A:82:65:62:72), so SW4 is root.Why the Other Options Are Wrong
A (SW1), B (SW2), and C (SW3) all have higher MAC addresses than SW4 once priority is tied, so they cannot be root.Community Comment Notes
The vote is D (100). Commenters confirm: first lowest priority, then lowest MAC, and SW4 has the lowest MAC.Official Reference
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