How is the integrity of a data packet evaluated in Ethernet?

In Ethernet, the integrity of a data packet is primarily evaluated using cyclical redundancy check (CRC). This method involves generating a short, fixed-length binary sequence, known as a checksum, from the data contained in the packet and appending it to the packet before transmission. When the packet is received, the receiving device recalculates the CRC value based on the received data and then compares it to the received CRC value.

If both CRC values match, it confirms that the data packet likely has not been altered or corrupted during transmission, ensuring data integrity. If there is a discrepancy, it indicates that an error has occurred, and the packet may be discarded or flagged for retransmission. CRC is widely used in network communications because it is efficient at detecting common errors that can occur during data transmission.

The other methods mentioned, such as timestamping, packet size checks, and address verification, do not directly assess the integrity of the data within the packet. Timestamping tracks when the packet was sent but does not check for data corruption. Packet size checks can determine if the packet conforms to expected sizes but do not validate the data itself. Address verification ensures that packets are sent and received by the correct devices but is not related to data integrity. Thus, CRC is