On May 26, 7:26 am, Harlan Stenn <st...@ntp.org> wrote: > >>> In article <jmydnbiifovm2ibxnz2dnuvz_gji4...@giganews.com>, "Richard B. > >>> Gilbert" <rgilber...@comcast.net> writes: > > Harlan Stenn wrote: > >> If you connect directly to an S1 server and that server goes insane, you > >> are screwed. If you connect to a well-configured S2 server you have a > >> lot better confidence that you'll be getting useful time. I recommend > >> you have as many of your machines as possible/reasonable peer with each > >> other. > > Richard> Does this really help unless each peer has at least one unique > Richard> source of time? > > I'm thinking of failure cases - it should leave a really big clique that > will outvote an insane server. > > It would be interesting to document various failure cases and see if we can > come up with a BCP document to describe these. > -- > Harlan Stenn <st...@ntp.org>http://ntpforum.isc.org - be a member!
About 10 years ago we used to have 2 seperate GPS receivers feeding into two Sparc servers via their serial port. I can't remember the version of NTP we ran however these were our stratum one servers, One of the Sparcs developed a fault on it's serial interface which delayed the input meaning the two stratum one servers started showing different time so all the statum 2 servers stopped trusting both stratum 1 servers as they could not determine which server, if any, was telling the truth. Ever since then we have always used at least 3 stratum one servers with seperate stratum zero sources to form a quorum so that startum 2 can differentiate the good from the bad. I believe this is set down as best practise in the ntp.org FAQ - this is a practical example of why this is wise. _______________________________________________ questions mailing list questions@lists.ntp.org https://lists.ntp.org/mailman/listinfo/questions