[ntp:questions] broadcast client

Unruh unruh-spam at physics.ubc.ca
Fri Sep 26 18:51:24 UTC 2008


rochertov at gmail.com writes:

>>
>> What this has to do with not believing in the algorithm I have no idea. If
>> ntp runs from a refclock that is EXACTLY the default behaviour. Running on
>> a local private network where you are referencing your own server, that
>> behaviour is also fine. The reason for the backup to long poll intervals is
>> a) to save the public servers from flooding, and b)to discipline the local
>> clock's drift rate in case there are long periods of disconnection from the
>> net. If you have constant connection and it is your own server, neither of
>> those apply, and short polling is better.

>Thanks, that is the answer I was looking for.  In our case, ntp load
>on the ntp server and the network is irrelevant.  We are just seeking
>the best synchronization possible, short of getting a PPS signal to
>every machine.  I will change the machine not to use broadcast mode
>and rely on min polling with maxpoll set to minpoll as well.  I will
>also enable iburst, as the docs indicate that it might increase
>performance by loading up the network a bit more.

On a local network, I doubt it. It would primarily "prime the pump" by
having the IP addresses/mac addresses already in the network system when
the ntp
packet is sent. But on a local network that would almost certainly not be a
problem, especially not with a poll interval of 16 sec. The decay time of
router memories is usually longer than that.
Now if you have 10^7 machines on your local net, then I might worry.




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