CompTIA Network+ (N10-007) — Question 90

Which of the following BEST describes the functionality of the root guard feature on a switch?

Answer options

• A. BPDUs entering the root bridge are ignored.
• B. The STP root bridge cannot be changed.
• C. Broadcast storms entering from a root port are blocked.
• D. Loop protection is enabled on the root port of a switch.

Correct answer: B

Explanation

The root guard feature ensures that the root bridge remains unchanged by preventing superior Bridge Protocol Data Units (BPDUs) from being accepted on ports where root bridge stability is critical. Options A, C, and D describe different aspects of STP functionality but do not accurately represent the specific role of root guard, which is to maintain the integrity of the root bridge position.