CCNA: Cisco Certified Network Associate — Question 543

When a switch receives a frame for an unknown destination MAC address, how is the frame handled?

Answer options

• A. flooded to all ports except the origination port
• B. forwarded to the first available port
• C. broadcast to all ports on the switch
• D. inspected and dropped by the switch

Correct answer: A

Explanation

When a switch encounters a frame with an unknown destination MAC address, it floods the frame to all ports except for the one it originated from, allowing it to reach the intended recipient if they are connected. The other options are incorrect as forwarding to the first available port does not apply to unknown addresses, broadcasting is not a precise term in this context, and inspecting and dropping is not the switch's standard behavior for unknown addresses.