CCNA: Cisco Certified Network Associate — Question 287

Why does a switch flood a frame to all ports?

Answer options

• A. The frame has zero destination MAC addresses.
• B. The destination MAC address of the frame is unknown.
• C. The source MAC address of the frame is unknown
• D. The source and destination MAC addresses of the frame are the same.

Correct answer: B

Explanation

The correct answer is B because a switch floods a frame when it does not know the destination MAC address, meaning it needs to send the frame out to all ports to find the correct recipient. Options A, C, and D are incorrect as they do not accurately describe the flooding behavior of the switch related to destination MAC address recognition.