Hi Alain, Bartholome, Alain wrote: > Hi, > > The primary reason why I need NTP is the synchronization of the systems, > not the accuracy of time. > > I need to simplify the maintenance of the systems as much as possible. > > I would like to know if it is mandatory to use the leap seconds mechanism > and installing the up to date leap file in order to have ntpd working > smoothly.
Basically the time used by NTP is assumed to be UTC. However, in fact it is just the time provided by the top level reference time source, so in a closed network you can distribute any time instead of UTC, with or without leap seconds, if you control the top level time source. In order to have NTP handle leap seconds correctly it is important that the leap second is announced properly. Once the top level NTP server is aware of the leap second it passes the announcement to its clients. In turn the clients can also act as NTP servers and cann pass the announcement on to their clients, after they have receive the announcement from their upstream server. You have to take care that the last client in the hierarchy receives the announcement before the leap second occurs. For examples, if there are 2 levels of clients below the top level server which are polling at long intervals of 1024 seconds then the top level server has to start to announce the leap second more then 2048 seconds before it occurs. Otherwise the last clients will miss it. If you have a GPS receiver as top level ref time source for the top level NTP daemon then the GPS receiver is internally aware of the upcoming leap second. The question is which protocol is used to pass the time string to the NTP daemon. E.g., AFAIK, the NMEA protocol does not support leap second announcements, so the server will not become aware of an upcoming leap second. In this case the leap second file (of course the current version) can make sure the top level server is aware of the leap second and starts to announce it down the client chain early enough. So if you use the file you're on the safe side, and the the effort to supply the file to the top level server should not be too hard. Martin -- Martin Burnicki Meinberg Funkuhren Bad Pyrmont Germany _______________________________________________ questions mailing list [email protected] https://lists.ntp.org/mailman/listinfo/questions
