<html><head><meta http-equiv="Content-Type" content="text/html charset=windows-1252"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><br class=""><div><blockquote type="cite" class=""><div class="">On 19 Oct 2016, at 14:28, Andreas Strikos <<a href="mailto:astrikos@ripe.net" class="">astrikos@ripe.net</a>> wrote:</div><br class="Apple-interchange-newline"><div class="">
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<div class="moz-cite-prefix">Hi Wenqin,<br class="">
<br class="">
that was a weird case where specific probe has time
synchronization issues. <br class="">
We saw a lot of debug messages in our raw logs coming from probe
complaining about time sync issues.<br class="">
If you have more examples including other probes please send us
details and we will happily check it for you.<br class="">
<br class="">
Regards,<br class="">
Andreas<br class="">
<br class="">
On 16/10/16 22:23, Wenqin SHAO wrote:<br class="">
</div>
<blockquote cite="mid:896954DF-0D51-448B-9A6E-7E28C47F2DE0@telecom-paristech.fr" type="cite" class="">
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charset=windows-1252" class="">
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial;" class=""><span style="font-kerning: none" class="">Hi list,</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial; min-height: 13px;" class=""><span style="font-kerning: none" class=""></span><br class="">
</div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial;" class=""><span style="font-kerning: none" class="">A couple of weeks ago, I
asked in this thread why some built-in measurements are
missing, or not performed at scheduled interval.</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial;" class=""><span style="font-kerning: none" class="">Cristel and Robert very
kindly shared what they thought could be the causes:
scheduling, probe reboot, updating task list, etc.</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial; min-height: 13px;" class=""><span style="font-kerning: none" class=""></span><br class="">
</div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial;" class=""><span style="font-kerning: none" class="">The discussion gave me the
idea to verify if there are as well missing measurements while
the probe is powered and connected to an Atlas controller,
i.e. probe seemly works in a good condition.</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial; min-height: 13px;" class=""><span style="font-kerning: none" class=""></span><br class="">
</div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial;" class=""><span style="font-kerning: none" class="">Here, I would like to
share one case among many I�ve observed where built-in
measurements are missed continuously for a long time, even
when the probe is well connected to a controller.</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial; min-height: 13px;" class=""><span style="font-kerning: none" class=""></span><br class="">
</div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial;" class=""><span style="font-kerning: none" class="">Let�s look at a time
window from '2016-06-16 21:53:20 +0000� to '2016-06-18
20:16:40 +0000� for probe 22144.</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial; min-height: 13px;" class=""><span style="font-kerning: none" class=""></span><br class="">
</div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial;" class=""><span style="font-kerning: none" class="">First, I queried its
connection events to Atlas controller (msm_id 7000).</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial;" class=""><span style="font-kerning: none" class="">The result says the probe
connected to a controller at '2016-06-16 21:54:19 +0000� and
became disconnected at '2016-06-18 20:13:48 +0000�. Between
these two moments, the probe is supposed to remain connected,
and thus continuously powered.</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial; min-height: 13px;" class=""><span style="font-kerning: none" class=""></span><br class="">
</div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial;" class=""><span style="font-kerning: none" class="">Then, I queried the
built-in ping measurements toward b-root (msm_id 1010) within
the time window.</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial;" class=""><span style="font-kerning: none" class="">Here below the timestamps
at which measurements are performed.</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial;" class=""><span style="font-kerning: none" class="">[�2016-06-16 22:51:08
+0000�, '2016-06-17 02:07:08 +0000�, '2016-06-17 03:11:02
+0000',</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial;" class=""><span style="font-kerning: none" class=""> '2016-06-17 04:03:07
+0000�, '2016-06-17 05:23:03 +0000�, '2016-06-17 07:35:17
+0000',</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial;" class=""><span style="font-kerning: none" class=""> '2016-06-17 10:51:06
+0000�, '2016-06-17 14:07:04 +0000�, '2016-06-17 15:11:03
+0000�,</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial;" class=""><span style="font-kerning: none" class="">'2016-06-17 17:23:06
+0000�, '2016-06-17 18:27:04 +0000�, '2016-06-17 20:39:04
+0000�, </span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial;" class=""><span style="font-kerning: none" class="">'2016-06-17 22:51:09
+0000�, '2016-06-17 23:55:03 +0000�, '2016-06-18 02:07:08
+0000',</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial;" class=""><span style="font-kerning: none" class="">'2016-06-18 03:11:04
+0000�, '2016-06-18 06:27:05 +0000�, '2016-06-18 08:39:02
+0000',</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial;" class=""><span style="font-kerning: none" class=""> '2016-06-18 10:27:13
+0000�, '2016-06-18 10:51:08 +0000�, '2016-06-18 11:55:13
+0000',</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial;" class=""><span style="font-kerning: none" class=""> '2016-06-18 12:03:13
+0000�, '2016-06-18 15:11:04 +0000�, '2016-06-18 17:23:05
+0000',</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial;" class=""><span style="font-kerning: none" class=""> '2016-06-18 18:27:09
+0000�, '2016-06-18 18:43:13 +0000�, '2016-06-18 19:35:18
+0000',</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial;" class=""><span style="font-kerning: none" class=""> '2016-06-18 20:15:06
+0000�]</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial;" class=""><span style="font-kerning: none" class="">We can see the intervals
between neighbouring measurements are much larger than the
planned value 240sec.</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial; min-height: 13px;" class=""><span style="font-kerning: none" class=""></span><br class="">
</div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial;" class=""><span style="font-kerning: none" class="">I investigated as well
other built-in ping measurements, say toward k-root (msm_id
1001). </span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial;" class=""><span style="font-kerning: none" class="">Here below are the
timestamps:</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial;" class=""><span style="font-kerning: none" class="">['2016-06-16 22:51:08
+0000�, '2016-06-17 02:07:07 +0000�, '2016-06-17 03:11:05
+0000',</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial;" class=""><span style="font-kerning: none" class=""> '2016-06-17 04:03:08
+0000�, 2016-06-17 05:23:03 +0000�, '2016-06-17 07:35:17
+0000',</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial;" class=""><span style="font-kerning: none" class=""> '2016-06-17 10:51:10
+0000�, '2016-06-17 14:07:04 +0000�, '2016-06-17 15:11:04
+0000',</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial;" class=""><span style="font-kerning: none" class=""> �]</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial;" class=""><span style="font-kerning: none" class="">Very similar phenomenon is
observed.</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial; min-height: 13px;" class=""><span style="font-kerning: none" class=""></span><br class="">
</div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial;" class=""><span style="font-kerning: none" class="">Between the first two
measurements in the above lists, there is an interval of more
than one hour, which can hardly be explained by measurement
secluding issue or temporarily high load.</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial;" class=""><span style="font-kerning: none" class="">What�s more, the probe
remained connected at those moments, therefore is free of
reboot and power-off..</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial;" class=""><span style="font-kerning: none" class="">As a reference, probe
12657 has all the measurements coming at due interval within
the time window.</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial;" class=""><span style="font-kerning: none" class=""><br class="">
</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial;" class=""><span style="font-kerning: none" class="">What could be the possible
causes behind such missing is my doubt. </span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial;" class=""><span style="font-kerning: none" class="">And I do appreciate your
thinkings on this so that the measurements can be processed
and analysed with propre caution.</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial; min-height: 13px;" class=""><span style="font-kerning: none" class=""></span><br class="">
</div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial;" class=""><span style="font-kerning: none" class="">Thanks.</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial; min-height: 13px;" class=""><span style="font-kerning: none" class=""></span><br class="">
</div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial;" class=""><span style="font-kerning: none" class="">Regards,</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial;" class=""><span style="font-kerning: none" class="">wenqin</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial; min-height: 13px;" class=""><span style="font-kerning: none" class=""></span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial; min-height: 13px;" class=""><span style="font-kerning: none" class=""></span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial; min-height: 13px;" class=""><span style="font-kerning: none" class=""></span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial; min-height: 13px;" class=""><span style="font-kerning: none" class=""></span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial; min-height: 13px;" class=""><span style="font-kerning: none" class=""></span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial; min-height: 13px;" class=""><span style="font-kerning: none" class=""></span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial; min-height: 13px;" class=""><span style="font-kerning: none" class=""></span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal;
-webkit-text-stroke-color: rgb(0, 0, 0);
-webkit-text-stroke-width: initial; min-height: 13px;" class=""><span style="font-kerning: none" class=""></span></div>
<div class="">
<blockquote type="cite" class="">
<div class="">On 02 Sep 2016, at 12:57, Robert Kisteleki <<a moz-do-not-send="true" href="mailto:robert@ripe.net" class="">robert@ripe.net</a>> wrote:</div>
<br class="Apple-interchange-newline">
<div class="">
<div class="">On 2016-09-02 12:20, Wenqin SHAO wrote:<br class="">
<blockquote type="cite" class="">Thanks for confirming.
The specified frequency is indeed well respected. When
there is no data-missing, the interval shift rarely
exceed 14s, small compared to 240s the scheduled
interval.<br class="">
What intrigues me is that the exact phase/timing is as
well kept after power cut and reboot.<br class="">
</blockquote>
<br class="">
The probes have a crontab-like mechanism to remember what
they need to do.<br class="">
As long as their clock is more or less ok, they will stick
to the<br class="">
pre-allocated times and tasks.<br class="">
<br class="">
<blockquote type="cite" class="">By the way, can a
measurement be as well skipped, as designed behaviour,
due to scheduling issues mentioned by @Cristel?<br class="">
</blockquote>
<br class="">
We're trying to avoid overloading probes, but not
everything is under our<br class="">
full control. Some measurements can pile up; Cristel &
Randy & co. had a<br class="">
paper about the observed (worst-case) behaviour.<br class="">
<br class="">
Regards,<br class="">
Robert<br class="">
<br class="">
</div>
</div>
</blockquote>
</div>
<br class="">
</blockquote><p class=""><br class="">
</p>
</div>
</div></blockquote></div><br class=""></body></html>