NTP is one of the most interesting and important, but all too forgotten, protocols that makes the internet tick. Accurate clock synchronization is required for everything ranging from cryptography …

NTP is one of the most interesting and important, but all too forgotten, protocols that makes the internet tick. Accurate clock synchronization is required for everything ranging from cryptography to business and science. NTP is closely tied around a handful of atomic clocks, some in orbit on GPS satellites, and some in laboratories. So the near-failure of one such atomic clock sparked a rather large, and nerdy, internet debate.

  • ravenaspiring@sh.itjust.worksEnglish
    11·
    9 hours ago

    As was designed, once utility power failed, backup generators took over. But as the outage dragged on, indications came to the scientists in charge of the atomic clocks at NIST that one of the generators had failed. This prompted scientists to warn against relying on the Boulder NTP sources. The scientists running the clock feared complete failure of the hydrogen source clocks. Such failure would require a lengthy and complex re-start procedure once power was returned in the long term, and complete failure of a stratum one NTP source in the short term.

    Further complicating the already bad situation was the fact that due to the dangers involved, the scientists could not reach the campus. So not only could they not confirm with certainty what issues the clocks may be experiencing, but they were unable to shut down the NTP servers. Fortunately, power was returned and the main source clock only drifted by a few microseconds. This is still far too much drift as would be preferred on a clock normally accurate in the range of nanoseconds, but perfectly usable for NTP which is only accurate to within a few milliseconds.

    And from Update on Boulder Internet Time Services and atomic time scale

    To put a deviation of a few microseconds in context, the NIST time scale usually performs about five thousand times better than this at the nanosecond scale by composing a special statistical average of many clocks. Such precision is important for scientific applications, telecommunications, critical infrastructure, and integrity monitoring of positioning systems. But this precision is not achievable with time transfer over the public Internet; uncertainties on the order of 1 millisecond (one thousandth of one second) are more typical due to asymmetry and fluctuations in packet delay.

    NIST provides high-precision time transfer by other service arrangements; some direct fiber-optic links were affected and users will be contacted separately. However, the most popular method based on common-view time transfer using GPS satellites as “transfer standards” seamlessly transitioned to using the clocks at NIST’s WWV/Ft. Collins campus as a reference standard. This design feature mitigated the impact to many users of the high-precision time signal.

    Fascinating stuff. Gives some answers to how long in a zombie apocalypse too, not that didn’t have them, and probably wouldn’t need highly precise time in that existence, but amazing anyway.