CRIO-9068 time synchronization and data timestamping - the Big Picture

Question

I'm working with a number of cRIO-9068 chassis that are distributed over a large physical area. I wish to timestamp data acquired be these chassis with microsecond resolution and relative accuracy. The various documents that I've run across hint at how this might be accomplished but none of them really describe the overall architecture for synchronization of chassis clocks over a network and acquisition of the local clocks for the purpose of data timestamping. Is there a document that addresses this topic?

Answer 1

http://www.ni.com/pdf/manuals/376007a.pdf:
Using the Internal Real-Time Clock
The system clock of the cRIO-9068 is synchronized with the internal high-precision real-time clock at startup. This synchronization provides timestamp data to the controller. You can also use the internal real-time clock to correct drift of the system clock. Refer to the Internal Real-Time Clock specification in the Specifications section for the accuracy specifications of the real-time clock.
What are the "system clock" and "real-time clock"? How are they related? How does the synchronization provide timestamp data to the cRIO-9068 controller? How does the internal real-time clock correct drift of the system clock?
http://www.ni.com/pdf/manuals/373185a.pdf:
No theory of operation whatsoever.
Note: https://forums.ni.com/t5/LabVIEW/cRIO-9068-amp-NI-TimeSync/td-p/2838178 suggests that NI-TimeSync may not be available for the cRIO-9068:
Currently NI-TimeSync 1.3 is not supported on Linux RT. This is something that's in the works but there is no ETA.