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Comment by adastra22 | Hacker News Reader

I know this is HN, but the internet is pretty low on the list of things NIST time standards are important for.

But pretty high on the list that NIST NTP is important for (since it leaves the building through the internet).

If NIST NTP goes down, the internet doesn’t go down. But atomic clocks drifting does upset many scientific experiments, which would effectively go down for the duration of the outage.

This is the reason GP listed out all the alternative robust NTP services that are GPS disciplined, freely available, and used as redundant sources by any responsible timekeeper.

What atomic clocks are disciplined by NTP anyway? Local GPS disciplining is the standard. If you're using NTP you don't need precision or accuracy in your timekeeping.

Also, I forgot to mention that NIST offers (and many institutions use) a service that provides a local rubidium reference that is GPS disciplined and they give you monthly reports that tell you the offset of the timestamps that were reported so they can be corrected. These services did not suffer interruptions.

could you list 3 things that you think are more important than the internet? (I know the internet is going to be fine; I just want to understand what you think ranks higher globally...)

Mostly scientific stuff like astronomical observations — e.g. did this event observed at one telescope coincide with neutrinos detected at this other observatory.

Note I didn’t say they are more important than the Internet. That’s a value judgement in any case. I said that NIST level 0 NTp servers are more important to these use cases than they are to the Internet.

All these use at least GPS for timing

No, they don’t. GPS is orders of magnitude less reliable than the most up to date metric time synchronization over fixed topology fiber links.

I wonder why we bothered building GPS signal waveguides into the bottom of a mine then. Clearly we should have consulted the experts of hacker news first.

Losing NTP for a day is going to affect fuck-all.

I'm not even sure why you're trying to argue this. It's well established that Time over Fiber is 1-2 orders of magnitude more accurate and precise than GNSS time. Fiber time is also immune to many of the numerous sources of interference GNSS systems encounter, which anyone who's done serious timekeeping will be well acquainted with.

Trying to argue that neutrino experiments use GPS time, because they do?

I’m sure synchronising all the worlds detectors over direct fiber links would… work, but, they aren’t.

Unless you are trying to argue internal synchronisation in which case, obviously, but that has absolutely zero to do with losing NTP for a day, the topic of conversation.

The deployments are still obviously limited, but this is something you can straight up buy if you're near a NIST facility [0]. I believe the longest existing link is NJ<->Chicago, which is used for HFT between the exchanges.

[0] https://shop.nist.gov/ccrz__ProductDetails?sku=78200C

I doubt that very much. GPS time integrity is a big deal in many very important applications -- not the least of which is GPS itself -- and is treated as such.

Yes, an individual fiber distribution system can be much more accurate than GNSS time, but availability is what actually matters. Five nines at USNO would get somebody fired.

The ability for humankind to communicate across the entire globe at nearly 1/4 of the speed of light has drastically accelerated our technological advancement. There is no doubt that the internet is a HUGE addition to society.

It's not super important when compared to basic needs like plumbing, food, electricity, medical assistance and other silly things we take for granted but are heavily dependent on. We all saw what happened to hospitals during the early stages of the COVID pandemic; we had plenty of internet and electricity but were struggling on the medical part. That was quite bad... I'm not sure if it's any worse if an entire country/continent lost access to the Internet. Quite a lot of our core infrastructure components in society rely on this. And a fair bit of it relies on a common understanding of what time "now" is.

I think it wont be affected by this but on the top of my head:

- GPS

- industrial complex that synchronize operations (we could include trains)

- telecoms in general (so a level higher than the internet)

GPS uses the atomic clocks on the satellites though.

(Random search result from space force https://www.ssc.spaceforce.mil/Newsroom/Article/4039094/50-y... claims that cell phone tower-to-tower handoff uses GPS-mediated timing (only microsecond level though.)

The satellite clocks are designed to run autonomously for a few days without noticeable degradation, and up to a few weeks with defined levels of inaccuracy, but they are normally adjusted once a day by the ground stations based on the timescale maintained by the USNO. That, in turn, uses an ensemble of H-masers.

In a past job I set up at least 5 domain dns servers pointing at nist ntp…

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