> On Mar 16, 2016, at 6:23 AM, Gabor Juhasz <gabor.sheph...@gmail.com> wrote: > > Hi All, > > In our IoT project we have to select an NTPd for our embedded device > in order it can have accurate time. > It uses 3G/4G mobile net. Of course the net is expensive so we have to > reduce the > network usage. Currently we have 2 candidates : OpenNTPd and Chrony. > > In OpenNTP (5.7p4) we are missing some features and we are looking > for some solutions > or workarounds to provide them. Do you have any idea how to do it with > OpenNTPd : > > * Maxchange > Maximum allowed offset corrected on a clock update. If the delta is > bigger ntpd exists.
I think you need to explain more about why you need this. I can guess, but that's not necessarily solving your problem. So hypothetically, you have a device that might have a big initial delta on boot, but might not have network access within the first 15 seconds of starting ntpd. Is that why simply using 'ntpd -s' at startup is not enough for this case? How would you know to trust any big jumps from NTP servers later on? Is your proposal to still only allow for a one-time initial setting (basically, make -s active forever until the time is initially set)? Otherwise, this opens a big hole. http://www.slideshare.net/jselvi/breaking-ssl-51430174 <http://www.slideshare.net/jselvi/breaking-ssl-51430174> > * Polltime > maxpoll /minpoll : setting the minimum/maximum polling interval > > * Offline mode > You tell the ntpd that network is not available. So it will not keep > trying to connect to ntp servers. > > Kind regards, > Gabor Juhasz
