[ntp:questions] Syncing and peering for a multi-continent deployment

David Taylor david-taylor at blueyonder.co.uk.invalid
Wed Apr 17 04:16:57 UTC 2013

On 10/04/2013 03:07, Blair Zajac wrote:
> Thanks Charles,
> OK.  So unless I go for some GPS-based clocks in my servers, each data
> center will use close stratum-2 servers and the stratum-3 clocks will
> not peer with clocks in my other datacenters.
> Regarding peering, then should each stratum-3 server in a single data
> center use all 4-7 upstream clocks?  Or should the 4-7 be split between
> the three stratum-3 servers?  The diagram at [1] suggests they should be
> split?   If that's the case, then how are falsetickers identified?
> Blair
> [1] http://www.ntp.org/ntpfaq/NTP-s-config-adv.htm#AEN3101

That diagram (figure 5) shows each of the local prime servers being fed 
from just two external sources, but as you say, 4-7 would be more 
sensible.  If it were me, I would go for one, two or three servers you 
know you can trust being in common across the stratum-3 servers, and 
fill in the rest with the "pool" directive.  This will fill up the 
servers with up to 10 external sources, which are dropped and an 
alternative automatically selected if the source goes bad.

I have information on my Web page about low-cost stratum-1 servers using 
Windows, FreeBSD and Raspberry Pi PCs.

Web: http://www.satsignal.eu

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