[ntp:questions] Re: Setting up a synchronization network

Hal Murray hmurray at suespammers.org
Fri Jan 16 07:39:13 UTC 2004

In article <7tydneoOcadc2prdRVn-uQ at comcast.com>,
 "Richard B. Gilbert" <rgilbert88 at comcast.net> writes:
>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.

Three servers lets you vote out a malicious bad guy.  If you
want to do that when one of the good guys is down, then you
need to start with 4 servers.

>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!

You don't really need that many until you have a pretty big empire
you need to keep in sync.  How big is your system and/or how important
is it to keep things in sync and/or how accurate do you need things
to be?
Several suggestions...

Check out www.pool.ntg.org

Ask your ISP about their NTP server.  If they say "Huh?" (not
unlikely) you might try to explain things to them and point out
that it's a good thing for ISPs to offer a good time server to
their customers.  (Beware of Windows servers.)

Consider getting a GPS clock and running your own stratum-1
server.  You can build your own if you are willing to tinker
or buy a ready-to-go box if you have cash and are short on time.

If you get your own GPS setup, then you have something to offer
in trade:

  Ask your ISP if any other customers have asked about NTP servers.
  If any of them have setup their own server, they are probably in the
  same situation as you and would be happy to find a local box to
  use as a reference in trade for letting you use their box.

  Ask in groups like this if anybody is local who doesn't have an
  public open policy will trade with you.

  Ask in local users groups and such.


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

Google for Z3801A.  (HP GPS box, available surplus from the cell phone
market.  Tinkering required.)

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