[ntp:questions] Synchronizing using servers in stratum 1 and 2

Timo Ruiter timo.ruiter at xs4all.nl
Sun Feb 11 15:18:46 UTC 2007

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?


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