[atlas] shared fate for my two probes

Hi,

My two RIPE Atlas probes have been acting strangely over the past
several months.  Very frequently I receive automatic notices from the
RIPE Atlas system that both of my probes have been "disconnected from
the RIPE Atlas infrastructure" essentially simultaneously.  Here's the
history from 2018:

probe 11171  2018-02-23 18:08:57 UTC.
probe 11203  2018-02-23 18:10:23 UTC.

probe 11171  2018-06-21 04:32:15 UTC.
probe 11203  2018-06-21 04:30:59 UTC.

probe 11171  2018-06-24 05:36:57 UTC.
probe 11203  2018-06-24 05:37:04 UTC.

probe 11171  2018-07-31 20:25:27 UTC.
probe 11203  2018-07-31 20:25:32 UTC.

probe 11171  2018-08-18 04:48:20 UTC.

probe 11171  2018-09-15 02:31:26 UTC.
probe 11203  2018-09-15 02:31:28 UTC.

probe 11171  2018-10-15 23:03:50 UTC.
probe 11203  2018-10-15 23:04:06 UTC.

probe 11171  2018-11-16 14:42:28 UTC.
probe 11203  2018-11-16 14:42:33 UTC.

(Those last three events are eerily periodic.)

Each time when I am finally able to visit inspect the probes (both are
reported as "Firmware Version 4940 (1100)"), their LEDs are in the
same state:

---------------

 Looking at the units with the on/off LED to the left:

  (1) the left-most (on/off) LEDs are on steadily.
  (2) the next LED is off.
 the next two LEDs are flashing at different frequencies:
  (3) the next flashes on approx. 48 times per minute
  (4) the next flashes on approx. 110 times per minute
  (5) the centers of the wide "WPS/RESET" LEDs are on steadily.

---------------

Once these probes fail they remain offline until I try turning it off
and on again.

The probes are powered similarly: the RIPE-provided USB cable is
plugged into an Apple iPhone USB power adapter, in turn plugged into a
standard US 120v / 60 Hz AC receptacle.  However, the AC power
circuits feeding these receptacles come from two very different
sources which should not share fate.

Until today both probes have been plugged into ports on the same Cisco
switch, but after today's disconnect I moved probe 11203 to a
different physical switch that has the same VLANs.

None of my other equipment experiences any troubles around the times
when these events happen to my RIPE Atlas probes.

In the past I have reported these events to atlas at ripe.net, but I
doubt that the causes cited (e.g. "the problem is with your dns") have
been accurate.  (I do not blame the atlas at ripe.net folks who have
responded.  Something strange is happening here, and I haven't yet
cracked it.)


I'm curious whether anyone else sees similar behaviors, or has
suggestions for ways to determine what is happening.

Thanks!

					Jay B.