CCNA: Cisco Certified Network Associate — Question 981

How does frame switching function on a switch?

Answer options

• A. floods unknown destinations to all ports except the receiving port
• B. buffers and forwards frames with less than 5 CRCs
• C. forwards frames to a neighbor port using CDP
• D. sends frames with unknown destinations to a multicast group

Correct answer: A

Explanation

The correct answer is A because switches send frames with unknown destination MAC addresses to all ports except the one that received the frame, ensuring that the destination, once learned, can be reached directly in the future. Option B is incorrect as CRC errors indicate transmission issues rather than a function of switching. Option C misrepresents the use of CDP, which is for neighbor discovery, not frame forwarding. Option D is also incorrect since unknown frames are not sent to a multicast group.