[ntp:questions] Syncing to nearby vs. faraway servers

Michael Sinatra michael at rancid.berkeley.edu
Mon Jun 15 22:41:02 UTC 2009

On 6/15/09 2:38 PM, Rich wrote:

> Is this sort of behaviour to be expected?  Does this mean that the NTP
> algorithm ought to be giving more weight to servers with shorter
> delays?  Or, perhaps, does it suggest that there might be something
> wrong with the Stanford servers that is making them all cluster around
> a time that is several milliseconds different from the rest of the
> world?

Keep in mind that the NTP protocol can't handle asymmetric round-trip 
delay.  It's more likely that the faraway servers have asymmetric paths 
to Stanford, which would explain their offsets.  (They are also more 
likely to have higher jitter.)

If you're actually on the Stanford network, you may want to use one of 
the public NTP servers on the CalREN network, since those servers are 
close by and their paths are likely to be symmetric.


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