[time-nuts] Minor NTP Issue?

Jason Rabel jason at extremeoverclocking.com
Mon Nov 1 20:01:50 UTC 2010


Poul-Henning & Russell,

Thanks for the inputs, and I'm pretty sure both of your responses are / could be attributing to the offset. Right now my GPS antenna
is mounted in a window and doesn't get the best view of the sky. After checking, each machine does think it is in a different
location (none of which are even close to right). Hopefully this weekend after the storms pass I can finally get around to mounting
my timing antenna outside where it will most definitely get a clear 360 view.

Interesting you mention 8 port switches... I have three of them in my network here... So yes that too could be a factor, I might
have to play around with the ports and see if that has any measurable effect.

Unfortunately I looked all through the TS2100 menus and couldn't find a compensation delay option, then I remember reading in the
latest firmware update they took that out... :(  Maybe I'll email Greg Dowd and see why they did that or if there's some hidden way
to adjust it.

Thanks again for the help!

Jason

> Once you get below 1ms you need to pay attention to everything, including
> ethernet switches.  For instance many 8 port switches consists of two
> five-port chips connected back to back.  That means that the packet
> delay inside a group is lower than between groups etc.

> Not sure if you have checked this, but I have found that I can see 
> 100us or more of delta if the dedicated clock has not done a position 
> average run, or has bad position information set.





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