On Tue, Feb 14, 2017 at 7:31 AM, MLewis <mlewis...@rogers.com> wrote:
> > > - a dedicated machine/box for unencumbered acceptance of PPS, and > - for systems with a business need, a dedicated NTP server/box disciplined > by the PPS source (with dedicated communication), while maintaining > internet NTP sources as backup for when the PPS source fails? > Is there a better way? > Other considerations? Don't ever think about "backup servers". NTP will always select the "best" reference clocks. The best ones are defined as the subset of references that track each other. Best practice today is to have two independent NTP servers and two GPS receivers. It is best if these are independent as you can make them, different buildings if you can. I would even use different brands of hardware to protect against a bug. Then throughout your company all your PCs are configured to look at both NTP servers Each server is configured to use the GPS reference clock, the other "twin" NTP server as well as about five Internet "pool" servers. If your location does not have an Internet connection. ( YES this can happen. I've worked on computers that process classified information and these computers never have Internet access.) You can configure them so they run in "orphan mode" that is they all use each other as reference clocks. Then when GPS is lost thenoormal NTP clock selection algorithm will select the subset of PCs that all agree on what the time is. The outliers tent to get ignored. When GPS comes back up the system makes a gradual and graceful recovery. Chris Albertson Redondo Beach, California _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
