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Internet of Things Endangered By Inaccurate Network Time, Says NIST
An anonymous reader writes: Current standards of network timekeeping are inadequate to some of the critical systems that are being envisaged for the Internet of Things, according to a report (PDF) by the National Institute of Standards and Technology (NIST). The report says, "A new economy built on the massive growth of endpoints on the internet will require precise and verifiable timing in ways that current systems do not support. Applications, computers, and communications systems have been developed with modules and layers that optimize data processing but degrade accurate timing." NIST's Chad Boutin likens current network accuracy to an attempt to synchronize watches via the postal system, and suggests that remote medicine and self-driving cars will need far higher standards in order not to put lives at risk. He says, "modern computer programs only have probabilities on execution times, rather than the strong certainties that safety-critical systems require."
That's assuming self-driving cars and medicine have any place at all on the internet.. Which they don't, if you ask me.
There is no "now" [1]. If you're relying on accurate timing from a network, you're already broken. If you require accurate local times, then you know that and know the error terms on your clocks. Standard OS clocks only tick at about 100hz, so you're always out by an average of 5ms anyways.
[1] https://queue.acm.org/detail.c...
I am a professional real-time embedded software engineer working with mission-critical networking devices. I don't buy the claims in the article because I don't understand _why_ internet-of-things devices need to have tight time sync or be real-time deterministic.
Accurate time sync is challenging - especially if you have wireless asymmetric links with non-deterministic latency.
Rather than trying to fix time sync, we should be questioning the reasons why we require tight sync to begin with. It is definitely necessary in certain situations, but those are far from the norm. In most cases where lives are not at stake, it's way easier and more sane to implement your system such that it does not need super accurate time sync.
Dice.com.
The clocks are hyper-accurate, world accessible and the technology is sufficiently robust and mature to be considered essentially bulletproof. It relies on a broadcast technology that scales to any number of receivers you care to connect and doesn't get bogged down by additional loading. Best of all it's managed and maintained by the US Government - but it works correctly anyway.