How does Ethernet perform error detection?

Ethernet uses the Frame Check Sequence (FCS) for error detection, which is a crucial protocol feature ensuring data integrity during transmission. The FCS is a 4-byte (32-bit) value that is calculated based on the content of the Ethernet frame before transmission. This value is generated using a cyclic redundancy check (CRC) algorithm, which helps in identifying any alterations to the frame that may occur due to noise, interference, or other factors during the packet's journey across the network.

When the frame reaches its destination, the receiving device recalculates the FCS value and compares it to the FCS included in the frame. If the values match, it indicates that the frame has likely been transmitted without errors. Conversely, if a discrepancy is noted, the receiving device can determine that an error has occurred and typically will discard the frame, prompting the sender to retransmit the data if necessary.

This method is efficient for networks, as it provides a reliable means for detecting errors with minimal overhead and does not involve the complexities or resource consumption associated with alternative methods. Using the FCS in Ethernet allows it to maintain a high level of performance and reliability in data communication.