[ntp:questions] frequency adjusting only

Steve Kostecke kostecke at ntp.org
Wed Apr 23 17:49:12 UTC 2008


On 2008-04-23, maxime louvel <m.louvel at gmail.com> wrote:

> The decision of buying a GPS is not mine ... So let's say for now
> that's still not possible, if no other solution is found I'll conclude
> that a GPS has to be bought.

I find it curious to hear people say that time stability is critical
to the functioning of their application/business/whatever and then, in
the next breath, say that they can't afford the requisite sub-$1000
solution.

> - I have chosen a broadcast configuration for two reasons :
>   - easier to install

The configuration for a leaf-node which polls a local time server is
arguably simpler than any *cast configuration.

>   - I am doing the tests on only 2 nodes, thus with broadcast I assumed that
> more nodes won't change the accuracy

A broadcast client calculates the delay correction from the server
during the intial unicast (i.e. client/server) phase of the association.
This delay correction is based on the network conditions at the time
the association is started. Broadcast packets sent during periods of
lighter, or heavier, network congestion/loading will receive a less than
correct broadcast delay correction.

One big advantage to unicast assciations is that each poll automatically
compenstates for the current network conditions.

-- 
Steve Kostecke <kostecke at ntp.org>
NTP Public Services Project - http://support.ntp.org/




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