[ntp:questions] IEEE 1588 (PTP) at the nanosecond level?

Martin Burnicki martin.burnicki at meinberg.de
Wed Mar 19 10:02:27 UTC 2014

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> Why not just NTP with a PTP RefClock Driver?
> People Already Run (& sell) Appliances that are both
>    PTP & NTP servers {which doesn't seem like it should be too hard};

I know. We at Meinberg are selling such appliances. ;-)

>   The question would be, which is disciplining the Appliance?

With special hardware it is not hard to get the accurate time via PTP 
into a device which also acts as NTP and PTP server. In fact it doesn't 
make much difference whether you use GPS or PTP as synchronization 
source, except for the absolute UTC offset which depends on the external 
PTP grandmaster, or the GPS receiver.

When the device then acts as a PTP server it can provide very accurate 
time to its slaves, but due to the missing NTP timestamping support on 
the network there is no benefit for NTP clients.

Martin Burnicki

Meinberg Funkuhren
Bad Pyrmont

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