[email protected] said: > NTP relies on network paths being symmetric -- the same latency from A to B > as from B to A. If the path is not symmetric, the result is an offset > error. Often the access link is inherently asymmetric such as ADSL. In > contrast, your DCF77 receiver suffers offset error due to propagation delay > between the transmitter and receiver, as well as delay getting the signal > into your computer. You cannot be sure your calibration is correct using > only network sources, due to the asymmetry likely present. You may be able > to come close by checking against different remote sources as you have tried > with PTB and the pool, but both share the access link from your premises > which may be the major source of error.
I think things work out right if you have an asymmetric path (ADSL?) and you synchronize your server over the network. The clock on the server will be off, but it's off in the right direction so that if somebody out on the net asks you for the time they get the right answer. The asymmetry cancels out. Can somebody confirm that? (I might have it backwards or...) -- These are my opinions, not necessarily my employer's. I hate spam. _______________________________________________ pool mailing list [email protected] http://lists.ntp.org/listinfo/pool
