[time-nuts] clock-block any need ?

Hal Murray hmurray at megapathdsl.net
Thu Dec 27 20:27:24 UTC 2012

attila at kinali.ch said:
> Here lies the big problem. While with GPS we pretty much know what the time
> is that the signal takes to reach earth, we have no clue with network
> packets in a loaded network.

I agree that if you are running on a busy network you are out of luck.

On the other hand, if the network is lightly loaded and the topology is 
stable, you can measure the round trip time and learn the unloaded time.  
Then you can ignore samples with longer round trip times.

> You can guestimate that getting below 200us is not easy in a normal network,
> but sub-1ms should be possible unless the network is very loaded. 

I can easily get ping times of under 150 us.  One switch.  I've got lots of 
ntp log files.  I should make a histogram.

These are my opinions.  I hate spam.

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