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semenkoyesterday at 9:20 PM6 repliesview on HN

I found the most interesting part of the NIST outage post [1] is NIST's special Time Over Fiber (TOF) program [2] that "provides high-precision time transfer by other service arrangements; some direct fiber-optic links were affected and users will be contacted separately."

I've never heard of this! Very cool service, presumably for … quant / HFT / finance firms (maybe for compliance with FINRA Rule 4590 [3])? Telecom providers synchronizing 5G clocks for time-division duplexing [4]? Google/hyperscalers as input to Spanner or other global databases?

Seriously fascinating to me -- who would be a commercial consumer of NIST TOF?

[1] https://groups.google.com/a/list.nist.gov/g/internet-time-se...

[2] https://www.nist.gov/pml/time-and-frequency-division/time-se...

[3] https://www.finra.org/rules-guidance/rulebooks/finra-rules/4...

[4] https://www.ericsson.com/en/blog/2019/8/what-you-need-to-kno...


Replies

dmurrayyesterday at 9:34 PM

I never saw a need for this in HFT. In my experience, GPS was used instead, but there was never any critical need for microsecond accuracy in live systems. Sub-microsecond latency, yes, but when that mattered it was in order to do something as soon as possible rather than as close as possible to Wall Clock Time X.

Still useful for post-trade analysis; perhaps you can determine that a competitor now has a faster connection than you.

The regulatory requirement you linked (and other typical requirements from regulators) allows a tolerance of one second, so it doesn't call for this kind of technology.

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throw0101cyesterday at 11:21 PM

> 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...

goaliecayesterday at 9:52 PM

My guess would be scientific experiments where they need to correlate or sequence data over large regions. Things like correlating gravitational waves with radio signals and gamma ray bursts.

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bob1029yesterday at 10:49 PM

> a commercial consumer

Where does it say these are commercial consumers?

https://en.wikipedia.org/wiki/Schriever_Space_Force_Base#Rol...

> Building 400 at Schriever SFB is the main control point for the Global Positioning System (GPS).

machinationuyesterday at 11:01 PM

science equipment, distributed radio-telescopes where you need to precisely align data received at different locations

mmaunderyesterday at 10:03 PM

SIGINT as a source clock for others in a network doing super accurate TDOA for example.