Andy, The flip answer is see Chapter 6 in my book. The useful answer is accuracy doesn't degrade that much, but reliability and diversity actually are actually enhanced. You're better off with a carefully watched core of primary servers, each located in a different regional center and a cloud of secondary servers at strategic sites around the country and a cloud of department servers at each site. That's the design I recommended for several large companies such as BCBXA, GTE, Bellcore and Merrill Lynch.
Dave Andy Yates wrote: >Does anybody have any figures that shows the effect on accuracy of an >NTP v3 client using a stratum 1 server rather than a stratum 2 or 3 >server? It's all in a GE LAN based scenario, commercial stratum 1 >servers connected to GPS and stratum 2 and 3 servers are typically >dedicated Linux boxes. > >The reasons is that I would rather scale by adding strata - its a very >big data center with thousands of clients and has several "zones" that >are isolated. However some opinion is suggesting we run IRIG-B between >the GPS receiver and a bunch of stratum 1 servers and clients access >these directly. Much more expensive and any increase in accuracy from a >client experience may be negligible. > >However I'm been pressed to supply an SLA for accuracy. My argument is >that although you can get your stratum one server to synchronize to >microseconds of UTP, as soon as the client uses NTP v3 over the LAN, >even a GE LAN, then the accuracy degrades and putting well designed well >specified stratum between the boxes is not going to decrease accuracy >sufficiently to warrant purchasing many stratum one appliances. > >Thoughts? > >Regards >Andy > >_______________________________________________ >questions mailing list >[email protected] >https://lists.ntp.org/mailman/listinfo/questions > > _______________________________________________ questions mailing list [email protected] https://lists.ntp.org/mailman/listinfo/questions
