CCNA: Cisco Certified Network Associate — Question 1059

How does MAC learning function?

Answer options

• A. sends the frame back to the source to verify availably
• B. rewrites the source and destination MAC address
• C. drops received MAC addresses not listed in the address table
• D. adds unknown source MAC addresses to the CAM table

Correct answer: D

Explanation

The correct answer is D because MAC learning involves adding unknown source MAC addresses to the Content Addressable Memory (CAM) table, allowing the switch to know where to send future frames. Option A is incorrect as MAC learning does not involve sending frames back to the source. Option B is wrong because MAC learning does not rewrite addresses; it learns and stores them. Option C is also incorrect since MAC learning allows new addresses to be added instead of dropped.