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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.
The network is not necessarily involved. The example given of a self-driving car talks about the amount of time taken to distinguish between a plastic bag blowing in the wind and a child running in front of the car. This is not "network" timekeeping, just regular real-time processing.
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...
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.
Anyone who is designing such systems around "accurate time" hasn't got a freaking clue how to build such systems.
For example, when dealing with spacing on self-driving vehicles, you rely on radar or laser tracking to maintain the separation between vehicles, not some wildly inaccurate network message about the velocity and position sent by other vehicles.
Medical in particular baffles me. Who in their right mind would design a medical system that synchronizes with anything other than the patient's own body rhythms?
But hey, that's what happens when you get some simulation designers trying to apply their single-clock logic to complex systems. They don't think about how real systems work -- the problem isn't an inaccurate time value -- it's an inaccurate understanding of the problem itself.
I do not fail; I succeed at finding out what does not work.
Exactly. The vast majority of Internet-of-Things devices can solve the problem by just installing ntpd and being done with it. My refrigerator or coffee maker or dehumidifier don't need hyper-accurate timing, and in the past year my devices running ntpd have never been more than around a tenth of a second off, which is still more accurate than anything that I actually need.
I get that you may need hyper-accurate timing for some things, but if something is so critical that a few milliseconds of clock skew can kill people, it shouldn't be connected to the Internet anyhow!
It covers a wide berth of timing related topics and is information dense. I found no marketing BS in this paper at all.