What type of checksum does UDP use for error-checking?

UDP (User Datagram Protocol) uses a 16-bit checksum for error-checking. This checksum is calculated by taking the data being transmitted, dividing it into 16-bit pieces, and then performing a one's complement sum of these pieces. If the total exceeds 16 bits, the overflow is wrapped around and added to the sum. The resulting value is then complemented to create the checksum, which is included in the UDP header.

When a UDP packet is received, the checksum is recalculated in the same manner using the received data. If the calculated checksum matches the one sent in the packet, it indicates that the data has not been corrupted in transit. If there's a mismatch, it signifies that an error occurred, prompting the packet to be discarded.

The significance of the 16-bit size is that it provides a reasonable balance between error detection capability and the overhead associated with including the checksum in the packet. A larger checksum, such as 32-bit or 64-bit, would offer more robust error detection but would also increase the size of the packet, affecting transmission efficiency. Conversely, a smaller checksum (like an 8-bit option) would not provide sufficient coverage to reliably detect errors in the transmitted data. Thus, the 16-bit checksum implemented in