[ntp:questions] Setting up a synchronization network

Richard B. Gilbert rgilbert88 at comcast.net
Fri Jan 16 02:09:09 UTC 2004


The conventional wisdom seems to be that one should have at least three 
servers, none having a time source in common with the others and that 
these three should be peers.

Do the arithmetic and we need nine servers at stratum 1 and/or 2.  The 
trouble is that there don't seem to be nine such servers available!  
With some effort I've found a stratum 1 server and two stratum 2 servers 
that are: open access, close to me in net-space, and provide pretty good 
time (most of the the time).  I'm in southern New Jersey, across the 
Delaware river from the Philadelphia Airport.  Our brand new T1 
connection goes to a "Point of Presence" (POP) in Philadelphia.  This 
has cut 2990 miles out of the network path I used to have!

There are no open access servers in Philadelphia!  There is one in NJ, 
one in DE, a bunch in NY, some even in NYC, and one in MA.

The NIST servers in MD are either too far away in net space or too 
heavily loaded, or both.  Ditto for the USNO in DC.  A server in PA 
seems to be wandering +/- 20msec in a vaguely sine shaped curve with a 
period of several hours; I'd like to be able to use him but NTP thinks 
he's insane at least half of the time!

What to do?  Buy a GPS receiver, a CDMA receiver and an "atomic clock"?  
Use one to synch each of the three servers I'm supposed to have? (I only 
have two at the moment.)

I don't really need the ultimate in accuracy and reliability but if it's 
worth doing, it's worth doing well!

(names have been withheld to protect the innocent)





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