Checksum Computation
The method used to compute the checksum is defined in RFC 768:
- Checksum is the 16-bit one's complement of the one's complement sum of a pseudo header of information from the IP header, the UDP header, and the data, padded with zero octets at the end (if necessary) to make a multiple of two octets.
In other words, all 16-bit words are summed using one's complement arithmetic. The sum is then one's complemented to yield the value of the UDP checksum field.
If the checksum calculation results in the value zero (all 16 bits 0) it should be sent as the one's complement (all 1s).
The difference between IPv4 and IPv6 is in the data used to compute the checksum.
Read more about this topic: User Datagram Protocol
Famous quotes containing the word computation:
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