[ntp:questions] SNTP with 1ms of precision?

Danny Mayer mayer at ntp.org
Thu Jul 8 02:46:01 UTC 2010

On 6/16/2010 5:22 PM, Maarten Wiltink wrote:
> "Marcelo Pimenta" <marcelopimentacs at gmail.com> wrote in message
> news:AANLkTilQ6M8ApEoaSIbr-o8mhwiFqKFV9xyf6MUDraDt at mail.gmail.com...
> [...]
>> The NTP algorithm is much more complicated than the SNTP algorithm.
> The short, short version: there is no SNTP algorithm. SNTP is NTP
> _without_ the algorithms. Using NTP means continuously adjusting the
> speed of your clock so it tracks real time as best you can make it,
> while SNTP is simply asking what time [they think] it is.

This is a totally inaccurate statement. See RFC 5905 Section 14. SNTP is
merely a subset of the full NTP protocol. An SNTP server is one with
it's own refclock and not dependent on any other upstream servers while
and SNTP client is one with a single upstream server and no dependent
clients. An SNTP client or an SNTP server should be disciplining the
clock in the same way as an NTP server. An SNTP server should
continuously adjust the speed of your clock otherwise it's not SNTP


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