DDSIRTP22 — Section: 9.3.2, Table 9.4

Page: 153
Change: In NTP, TIME_ZERO represents a point in time in 1900. If this was followed by RTPS with its 31-bit field for positive seconds, the maximum point in time would be in 1968, long before RTPS was invented. Therefore the meaning of TIME_ZERO must be specified here. Additionally, leaving only 31 bits for positive seconds and assuming 1970 is used as TIME_ZERO, RTPS times are only valid through 2038. Is there a need for a sign bit in “seconds”?

The format used is similar to NTP in that is uses seconds and fractions of a second
(to make arithmetic simple) rather than seconds and nanoseconds. However it uses
a signed seconds such that signed arithmetic can be applied.
For these reasons and to facilitate conversion to operating system times (timeval and
timespec) the time origin TIME_ZERO is defined to be the Unix prime epoch 0h, 1
January 1970