Which mechanism provides an error-check value used to determine whether a frame arrived uncorrupted?

• A. Cyclic Redundancy Check (CRC)
• B. Hash-based Integrity
• C. Parity Bit
• D. Checksum

Answer: (A)

Error-detection for frames relies on a specific check value attached to the data so the receiver can confirm integrity after transmission. A Cyclic Redundancy Check uses a generator polynomial to compute a short remainder, which is appended to the frame. Upon arrival, the receiver runs the same calculation over the entire frame (data plus the CRC) and checks the remainder. If it zeroes out, the frame is considered uncorrupted; if not, an error is detected. CRCs are designed to catch both random bit errors and burst errors with a high probability and are efficient for hardware or software implementations, which is why they’re widely used for per-frame integrity checks in networks.

A parity bit provides a minimal form of error detection, capable of catching odd numbers of bit flips but missing many error patterns, especially burst errors. A checksum is a simpler, additive method that can detect many errors but isn’t as robust against certain patterns as CRC. Hash-based integrity checks offer strong data integrity guarantees but are heavier to compute and are typically used for end-to-end data integrity rather than per-frame error detection in transit.