[ntp:questions] NTP vs chrony comparison (Was: oscillations in ntp clock synchronization)

Brian Utterback brian.utterback at sun.com
Fri Jan 25 15:38:34 UTC 2008

Danny, I agree with everything you said except:

Danny Mayer wrote:
> I agree. I don't see how it can be a specification violation. The 
> biggest factor is how well it keeps time. A caesium clock keeps good 
> time but you wouldn't say that it violates the specification.

When we first started looking at the V4 spec for the ntp-wg, my first
thought was the same as yours, namely that what happens inside a system
shouldn't matter, the algorithms don't matter, only what it chimes
matters. And strictly speaking, this is true. However, after reading
Dave's book (Das Buch as he calls it), I realized that an important
factor to the stability of the NTP network is the actual speed at
which the clocks slew, i.e. the 500 PPM limit. This is largely
ignored in the spec. I sent in some comments about how I thought it
should be addressed but alas, my changes didn't make it in the latest

Brian Utterback

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