A physicist I know that works in a government institution recently commented that they have a cesium clock, and they were considering the possibility of setting up a public stratum 1 NTP server attached to it.

However they (and I) were wondering about the benefits/usefulness of doing that. As a developer, I never needed to use NTP directly so my knowledge of it is rather vague. As far as I know there are only a few NTP servers in this country (Argentina), but I know that NTP compensates for network latency, so is there any benefit to having a closer server?

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    There's a benefit, but what's their need? – mfinni Jan 21 '14 at 17:11
  • @mfinni so if there's a benefit, what is it? – Mauricio Scheffer Jan 21 '14 at 17:13
  • You depend on the NTP software correction less, as you stated. The benefit, as I think should be obvious, is more accurate time readings. If they will actually benefit from that, we can't say, as you haven't told us if they are actually trying to solve a problem, or are just looking to do it because they can. – mfinni Jan 21 '14 at 17:19

This is a highly opinion-seeking question, but I'll answer anyway.

I run an NTP pool server. It's one of a large number in the UK and European pools, but it's pretty heavily used - this is the number of unique clients making requests every second over the past year:

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Even in the highly-industrialised countries, there is always a need for more pool servers; outside that region there's even more of a need, if traffic on the pool mailing list is anything to go by. If you have a stratum-0 clock, and don't mind strapping it to a unix box and making a public stratum-1 server, it'll be a service to the internet as a whole.

Moreover, as others have pointed out, being a predictable round-trip from an NTP server improves one's own synchronisation. Round-trip latencies tend to get less predictable when congested links become involved, and long-distance links are often the most congested, so your server will be particularly useful for people in South America; Argentinians most of all.

Running it through the NTP pool system minimises the workload involved, since the pool monitoring system will pull you from the pool if you lose sync or start to advertise a crazy time.

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    I would like to humbly add to this excellent answer that, depending on how the NTP links through ISPs and which ISPs are prevalent where in Argentina, the risk of becoming stratum-1 less in Argentina through ISP peering wars could be lessened. As decoupling could have both business and political motives, this could increase national community value if properly prestudied. Here are some lessons learned in a recent US-Swedish business driven peering war: renesys.com/wp-content/uploads/2013/05/nanog43-peeringwars.pdf – ErikE Jan 21 '14 at 17:32

In my humble opinion, the quality of computer clocks has improved sufficiently over the past decade and there are now quite a number of volunteer and professionally run NTP servers.

Running a public NTP server is comitting to looking after it. If people can't rely on it then there's little point in running it. If people are to count on it, it needs to be looked after - which can be inconvenient if it breaks at the wrong time.

NTP is best with a constant or predictable round trip time. Doesn't so much matter how long as long as it's consistent.

Definitely don't throw it away. But, unless any of you have needs for a more precise and accurate clock than what your computer+ntp can give you, then no, there isn't much point.

  • +1: "Running a public NTP server is comitting to looking after it." – longneck Jan 21 '14 at 17:19
  • @longneck true, but the utility of the service to the people expecting to use it is still relevant. – etherfish Jan 21 '14 at 17:20

If the cesium clock does not supply NTP (built in server) then you must have it input to your, perhaps Linux, NTP server which will be a Stratum 1 server. But to be a ligit stratum 1 server it must trace it's time back to the world's and national master clocks, such as at NIST in the U.S. Of course the GPS satellites are maintained as valid master clock sources. If your cesium can be 'disciplined' by the GPS satellites over time then it can become more accurate than a short term GPS satellites 'connection' if you will and be built as quite superior stratum 1 server. On the short term, the cesium can probably be 'trusted' over the GPS signal and even over GPS receiver bugs (which we have seen).


Benefit of closer ntp server: accuracy and precision of time synchronization.

Benefit of additional servers: allows for ntp clients to detect if a server is misbehaving.

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