[ntp:questions] NTP tunning for OWD measurements

pret3nder at gmail.com pret3nder at gmail.com
Sat Oct 27 16:37:00 UTC 2012


OWAMP can refer to One-Way Active Measurement Protocol,
see http://tools.ietf.org/html/rfc4656, or the tool that follows
that protocol to measure one-way delay, 
see http://www.internet2.edu/performance/owamp/

NREN, as stated before, means National Research and Education Network.

@unruh: yes, I was talking in the range of microseconds,
not single microsecond accuracy!
This is the current output of ntpq -p on X1 server:

[alias at x1 ntp]# ntpq -p
     remote           refid      st t when poll reach   delay   offset  jitter
=============================================
*time01.nren.pt  .DCFa.           1 u    7   16  377    5.661    0.021   0.015
 time02.nren.pt  .DCFa.           1 u    6   16  377    1.240    0.078   0.026
 time04.nren.pt  .DCFa.           1 u    2   16  377    2.324    0.102   0.009
 time03.nren.pt  .DCFa.           1 u    -   16  377    8.757    0.109   0.011

If the delay, offset and jitter values are shown in milliseconds,
I am led to believe X1 currently has an offset to time01 stratum
1 server of 21 microseconds, right? If S1 has the same offset,
I can expect a maximum error of 42 microseconds on the owd 
measurements, ignoring the errors caused by the delay asymmetry.
Is this correct?

Pedro

On Saturday, October 27, 2012 5:19:09 PM UTC+1, Richard B. Gilbert wrote:
> On 10/26/2012 5:56 PM, pret3nder at gmail.com wrote:
> 
> > Hi all, and thank you for your answers. I'm afraid I might not have
> 
> > been clear about my objectives, so I'll try to explain clearer.
> 
> > I'll also try and keep the lines smaller, and please, excuse me if
> 
> > I make any mistakes, as english is not my native language.
> 
> >
> 
> > This project involves a NREN, which interconnects several institutions.
> 
> 
> 
> I give up?  WHAT IS "NREN"?????
> 
> 
> 
> <snip>



More information about the questions mailing list