Which frame forwarding method receives the entire frame and performs a CRC check before forwarding the frame?

• A. Cut-Through
• B. Fragment-Free
• C. Fast-Forward
• D. Store-and-Forward

Answer: (D)

This question tests how frame forwarding methods handle error checking with the Frame Check Sequence (CRC). In store-and-forward switching, the switch buffers the entire Ethernet frame, runs a CRC to verify its integrity, and only forwards the frame if the CRC passes. This ensures corrupted frames aren’t forwarded, preserving network hygiene.

In contrast, cut-through forwards the frame as soon as the destination MAC address is read, before the CRC is checked, so a damaged frame could be sent. Fragment-free waits for the first 64 bytes to avoid forwarding runt frames caused by collisions, but it still doesn’t rely on a full CRC check before forwarding. Fast-forward is a fast variant of cut-through that starts forwarding after reading the destination address, aiming for lower latency.

Therefore, the method that receives the entire frame and performs a CRC check before forwarding is store-and-forward.