Dave Hart wrote: > NTP includes error budget calculations at every level. You should be > able to demonstrate the difference between directly using a stratum 1 > appliance compared to using higher-strata intermediate NTP servers > simply by observing the root dispersion on the client. > > I suspect you are correct that the benefit is not worth the cost, but > convince yourself with measurement. Using FreeBSD instead of Linux > for the intermediate servers will probably give better results, if > that is a possibility, give that a test as well. > > I would also encourage you to consider using NTPv4 in preference to > NTPv3 where it is practical, but especially on the intermediate > servers. A lot has improved in NTP since version 3. > > Finally, while it is true you can improve scalability using broadcast > or multicast, it also requires extra configuration to provide matching > keys on both sides, or using the "disable auth" option which is not > recommended. NTP uses very few resources even with hundreds or > thousands of unicast clients, as each client polls at most once per > minute and typically, after stabilizing, once per 17 minutes (1024 > seconds for default maxpoll 10). Processing each packet and replying > is very fast, so even after a power outage when many clients are > starting at once, I would expect even relatively decrepit hardware to > have no problem keeping up with the traffic. With 10,000 clients > polling a single server every 64 seconds, the average rate is 156 > packets per second in and out each 48 bytes long. I bet your existing > servers could handle that rate easily. > > Cheers, > Dave Hart
Many thanks for your help Dave Your comments make sense. BTW the NTP v3 was only to take into account end clients, many of which I believe are still v3 - I could be wrong, I would use v4 for any intermediate strata. Regards Andy _______________________________________________ questions mailing list [email protected] https://lists.ntp.org/mailman/listinfo/questions
