If a frame is received but fails CRC verification, which steps should you perform?

• A. Ignore the CRC error and continue
• B. Only log the error and wait for manual intervention
• C. Verify sender CRC calculation, inspect payload integrity, check for bit flips, and consider retransmission and alternate paths
• D. Restart the entire system

Answer: (C)

When a frame arrives with CRC verification failing, the priority is to diagnose and recover rather than treat it as valid data. Start by checking the sender’s CRC calculation to ensure the CRC was computed with the correct polynomial and parameters and that the transmitted CRC matches what the sender intended. Then inspect the payload integrity to see if there are signs of corruption beyond the CRC, and consider whether a bit flip or noise on the link could have altered the bits. Finally, pursue reliability by considering a retransmission and, if possible, an alternate path or route to get the data through correctly.

Ignoring the CRC error would risk processing corrupted data. Logging alone delays resolution and doesn’t recover integrity. Restarting the entire system is unnecessary for a single-frame error and is an overreaction to the issue.