[Maxious]

There's two other sites for the time.nist.gov service so it'll be okay.

Probably more interesting is how you get a tier 0 site back in sync - NIST rents out these cyberpunk looking units you can use to get your local frequency standards up to scratch for ~$700/month https://www.nist.gov/programs-projects/frequency-measurement...

[lovich]

What happens in the event all the sites for time.nist.gov go down? is it included in the spec?

Also thank you for that link, this is exactly the kind of esoteric knowledge that I enjoy learning about

[sdrmill]

Most high-availability networks use pool.ntp.org or vendor-specific pools (e.g., time.cloudflare.com, time.google.com, time.windows.com). These systems would automatically switch to a surviving peer in the pool.

Many data centers and telecom hubs use local GPS/GNSS-disciplined oscillators or atomic clocks and wouldn’t be affected.

Most laptops, smartphones, tablets, etc. would be accurate enough for days before drift affected things for the most part.

Kerberos requires clocks to be typically within 5 minutes to prevent replay attacks, so they’d probably be ok.

Sysadmins would need to update hardcoded NTP configurations to point to secondary servers.

If timestamps were REALLY off, TLS certificates might fail, but that’s highly unlikely.

Databases could be corrupted due to failure of transaction ordering.

Financial exchanges are often legally required to use time traceable to a national standard like UTC(NIST). A total failure of the NIST distribution layer could potentially trigger a suspension of electronic trading to maintain audit trail integrity.

Modern power grids use Synchrophasors that require microsecond-level precision for frequency monitoring. Losing the NIST reference would degrade the grid's ability to respond to load fluctuations, increasing the risk of cascading outages.

[neomantra]

Great list! Just double-checked the CAT timekeeping requirements [1] and the requirement is NIST sync. So a subset of all UTC.

You don’t need to actually sync to NIST. I think most people PTP/PPS to a GPS-connected Grandmaster with high quality crystals.

But one must report deviations from NIST time, so CAT Reporters must track it.

I think you are right — if there is no NIST time signal then there is no properly auditable trading and thus no trading. MFID has similar stuff but I am unfamiliar.

One of my favorite nerd possessions is my hand-signed letter from Judah Levine with my NIST Authenticated NTP key.

[1] https://www.finra.org/rules-guidance/rulebooks/finra-rules/6...

[3eb7988a1663]

Considering how many servers are in existence, probably the exact same procedure for starting a brand new one?

[wpm]

I must have one of those units oh my god

[mh-]

Someone needs to sell replicas (forgive the pun) of these.

[wat10000]

It's like a toaster oven, but it toasts time.