[ntp:questions] NTP tunning for OWD measurements

pret3nder at gmail.com pret3nder at gmail.com
Fri Oct 26 15:17:51 UTC 2012


I'm sorry, I was writing this in Google Groups web interface.

Maybe I didn't explain myself correctly: I don't want to use external time sources, only NTP,
with the best tuning (and not tunning :D) possible. But I do have access to four stratum 1 servers, using
GPS and PPS inputs, which I use as servers to synch my hosts to.

Kind Regards,
Pedro

On Friday, October 26, 2012 3:44:13 PM UTC+1, David Woolley wrote:
> pret3nder at gmail.com wrote:
> 
> > 
> 
> > my name is Pedro Queirós and I'm currently working on my master
> 
> > thesis
> 
> + related to open source probes to measure the QoS of internet link.
> 
> 
> 
> [ Your lines are too long. In internet mail, and other standards based 
> 
> on it, CRLF delimits lines, not paragraphs. ]
> 
> 
> 
> > One of the tools I'm using is OWAMP
> 
> + (http://www.internet2.edu/performance/owamp/), to measure one-way delay
> 
> + between hosts. This tool requires NTP running and synchronizing clocks
> 
> + so that it can measure correctly (to a certain point) the one-way delay
> 
> + between hosts.
> 
> 
> 
> You need directly attached radio clocks, and for GPS, you will need PPS. 
> 
>    You will need these on the actual machine, although, if you have 
> 
> older Ethernet hardware, the same LAN may be better than nothing.  NTP 
> 
> cannot correct for systematic one way delays.



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