When store-and-forward switching is used, which part of the frame is used to verify errors?

When store-and-forward switching is used, which part of the frame is used to verify errors?

• A. CRC in the trailer
• B. Source MAC address in header
• C. Destination MAC address in header
• D. Protocol type in header

Answer: (A)

The CRC in the trailer is used to verify errors. In store-and-forward switching, the switch waits until it has the entire frame, then checks its integrity by recomputing the Frame Check Sequence (CRC) that the sender placed in the trailer. If the computed CRC matches the trailer, the frame is considered error-free and can be forwarded; if not, the frame is dropped. The header fields (Source MAC, Destination MAC, Protocol type) are for addressing and protocol purposes, not for error verification.

The CRC in the trailer is used to verify errors. In store-and-forward switching, the switch waits until it has the entire frame, then checks its integrity by recomputing the Frame Check Sequence (CRC) that the sender placed in the trailer. If the computed CRC matches the trailer, the frame is considered error-free and can be forwarded; if not, the frame is dropped. The header fields (Source MAC, Destination MAC, Protocol type) are for addressing and protocol purposes, not for error verification.