On 10/26/2012 6:47 PM, pret3n...@gmail.com wrote:
I'm sorry, I'm not following you. What delay asymmetry are you refering to?
OWAMP does rely on accurate time stamps, see
http://www.internet2.edu/performance/owamp/index.html
If I have S1 and X1 synching to the same time reference (in this case,
the same stratum 1 server), and I do one-way delay tests between S1 and X1,
I'm expecting to find a valid measurement of the one-way delay, no?
If you're talking about the asymmetry caused by NTP assuming the one-way delay
to/from the clients is RTT/2, I'm aware of that error. And I will try to
minimize it,
e.g., using tunnels.
On Friday, October 26, 2012 11:19:26 PM UTC+1, David Woolley wrote:
pret3n...@gmail.com wrote:
Also, I don't want to use NTP to directly measure the one-way delay, I have
OWAMP
You can't stop it measuring the delay asymmetry! The trouble is you
will not have any way to obtain that value, which will tend to cancel
out the asymmetry measured by your primary tool, assuming it depends on
accurate time stamps!
(more specifically perfSonar - http://www.internet2.edu/performance/pS-PS/)
to do that for me.
The page is a commercial type hype, not a technical overview of the
algorithms used, but the only way I know of measuring one way delay is
synchronise the clocks somewhat better than the acceptable measurement
error, which you can't do if the synchronisation process is vulnerable
to the effects of the same delay asymmetry.
On Friday, October 26, 2012 11:19:26 PM UTC+1, David Woolley wrote:
pret3n...@gmail.com wrote:
Also, I don't want to use NTP to directly measure the one-way delay, I have
OWAMP
You can't stop it measuring the delay asymmetry! The trouble is you
will not have any way to obtain that value, which will tend to cancel
out the asymmetry measured by your primary tool, assuming it depends on
accurate time stamps!
(more specifically perfSonar - http://www.internet2.edu/performance/pS-PS/)
to do that for me.
The page is a commercial type hype, not a technical overview of the
algorithms used, but the only way I know of measuring one way delay is
synchronise the clocks somewhat better than the acceptable measurement
error, which you can't do if the synchronisation process is vulnerable
to the effects of the same delay asymmetry.
On Friday, October 26, 2012 11:19:26 PM UTC+1, David Woolley wrote:
pret3n...@gmail.com wrote:
Also, I don't want to use NTP to directly measure the one-way delay, I have
OWAMP
What is OWAMP?
<snip>
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