Ethernet UDP checksum compensation

摘要

In the methods and devices of the present disclosure, a dummy compensation word is added to the data packet such that the UDP checksum value need not be modified from any previous value, regardless of changes to the UDP payload. Because the UDP checksum value is not modified in embodiments of the present disclosure, there is no delay waiting for a UDP checksum value to be calculated and no need for additional buffers to store the data packet contents because of UDP checksum calculations. The dummy compensation word is calculated so that the unmodified value maintained in the checksum is the checksum for the data packet including the dummy compensation word. By placing the compensation word in the data packet after the last word in the UDP payload, there is no, or very minimal, processing delay and data packet buffering hardware is significantly reduced.

主权项

1. A method for checksum calculation of a data packet comprising a plurality of digital information units including a checksum and a payload, the method comprising:
(a) reading the packet unit by unit, including reading the checksum; (b) accumulating the units being read in (a) to a running sum according to a checksum calculation formula for the data packet; (c) calculating a compensation value from the running sum of (b) such that including the compensation value in the running sum validates the checksum read in (a); (d) adding an extra digital information unit in the data packet near an end of the payload; and (e) storing a compensation value in the extra digital information unit.