> I've never heard of this! Very cool service, presumably for … quant / HFT / finance firms (maybe for compliance with FINRA Rule 4590 [3])?
To start with, probably for scientific stuff, à la:
* https://en.wikipedia.org/wiki/White_Rabbit_Project
But fibre-based time is important in case of GNSS time signal loss:
* https://www.gpsworld.com/china-finishing-high-precision-grou...