Timo Ruiter schreef: > Hi all, > > When using pool.ntp.org the DNS randomly select time servers. Since > stratum-1 servers and stratum-2 servers share the same pool you will get > a mix of them when using 0.nl.pool.ntp.org, 1.nl.pool.ntp.org, and > 2.nl.pool.ntp.org for instance. > When you are assigned *one* stratum-1 server and *two* stratum-2 servers > your clock will obviously synchronize to the stratum-1 server. But that > being the case, what is the use of the two stratum-2 servers, assuming > that the stratum-1 server will not go off-line? > Could it be so that if the stratum-1 server is not so accurate after all > it would still be selected over the stratum-2 servers (since no > reference stratum-1 server is available)? > Will you not be better served instead when you are assigned *three* > stratum-2 servers, so the selection process of ntpd will compare all > three servers equally and choose the best one, switching to another if > that one looks more stable after a while? > > > Regards, > Timo What I really wanted to know is what is better in terms of stability: *one* stratum-1 server and *two* stratum-2 servers versus *three* stratum-2 servers. When having only one stratum-1 server available you might be relying on that server too much; when having three stratum-2 servers (ideally synchronized to three different stratum-1 servers) time *could* be more stable since there are three stratum-1 servers involved, albeit through the stratum-2 servers.
This is a pure theoretical issue as far as I'm concerned, since who can tell the difference if your servers are 23 milliseconds off... So replace "stratum-1" by "stratum-N" and "stratum-2" by "stratum-(N-1)"; the question will remain the same. Regards, Timo _______________________________________________ questions mailing list [email protected] https://lists.ntp.isc.org/mailman/listinfo/questions
