[ntp:questions] Poll timing

Jussi Kauppinen jtkauppi at cc.hut.fi
Thu Aug 16 11:01:40 UTC 2007

Paul.Croome at softwareag.com wrote:
> Jussi,
> Why should the exact instant when NTP polls be important? It doesn't
> matter whether the polling interval is 64 seconds or 64.1 seconds or
> whatever.
> IIRC, there is some logic in NTP that deliberately staggers the
> polling of servers when NTP starts up. If this were not done, NTP
> would try to poll all its servers more-or-less simultaneously,
> causing
> bursty network traffic. See
> http://www.eecis.udel.edu/~mills/ntp/html/ntpd.html#op: "In order to
> protect the network from bunching, the initial poll interval for each
> server is delayed an interval randomized over a few seconds."
> Paul

I'm developing a system that utilize NTP. Unfortunately, the details of 
the system are confidential. For this system to work properly, it is 
essential that polling phase inside a second is approximately constant 
related to the clock of the client, like I explained earlier. I'm using 
only one NTP server to poll from.

Can you tell me what files/parts/functions in the source code do the 
polling, from where I can check it out how the timing works.


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