[time-nuts] Embedded NTP servers?

Michael Tharp gxti at partiallystapled.com
Sun Aug 19 14:19:42 EDT 2012


On 08/19/2012 01:38 PM, Chris Albertson wrote:
> NTP is not as easy as you think.  Just doing the cryptography to handle
> authentication is more then I would want to write.  When a free open source
> ntpd exists it will be really hard to get people to help work on
> re-inventing it.  But your idea to use a GPSDO to drive the system clock is
> good.  People have done that and it works. You basically unsolder a TTL
> "can oscillator" and put a small connector in it's place.

This is specifically *not* a full ntp implementation. There's no client, 
no PLLs or clock correction, nothing but using 10MHz+PPS+NMEA to feed an 
internal clock and serving it out over ntp to more intelligent clients. 
I haven't written any code yet but from nosing around in wireshark it 
seems like the ntp part of the project wouldn't take more than an hour 
or two to write. The only tricky part is keeping a calendar so it knows 
when to insert a leap second.

I'm not initially interested in authentication, although I do have all 
my PCs at home running in authenticated broadcast mode. So I might add 
auth later so it can participate, but I would be satisfied without it.

-- m. tharp




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