How do I diagnose intermittent connection drops?

2

I'm continuously retrieving data from a remote sensor connected over Ethernet via a switch. I see that about twice per hour, the connection breaks down for a couple of seconds.

I know that the remote sensor doesn't reboot (it would log this), but I can't ping it anymore. Now I need to know if my connection to the Ethernet switch breaks down, or if it's the network connection of the sensor.

Any idea how?

fschmitt

Posted 2016-04-25T07:11:56.107

Reputation: 131

1A little script: ping to the sensors with the counter set to 1 (only one ping). If up wait nn seconds and repeat. If ping doesn't answer then ping to a well known and working ip (e.g. 8.8.8.8). If it answers it is down the connection with the sensors, if it doesn't it is down the internet connection. – Hastur – 2016-04-25T09:44:36.843

That's a good idea actually. I can just connect something to the switch where i'm rather sure it's stable. Than I run two endless ping commands, one to the sensor, one to the know good device. If I see timeouts in both, it's the PC or the switch. If it's only the sensor, it's the sensor. – fschmitt – 2016-04-25T10:53:02.313

Try with a ping with interval of 1 second. Catch the exit status (in bash $?) or use it directly. In a one line bash while : ; do ping -c 1 ip_sensor || ping -c 8.8.8.8 && echo " Sensor Down" || echo " Internet down" ; sleep 1s; done. Translate it for windows or use a bash under windows (cygwin, native if win 10, virtual machine [ok the last one too much :-) ]). – Hastur – 2016-04-25T11:08:57.687

Answers

0

If you suspect the switch, you would really need to swap it out to test, as switches can't be seen in the IP path. That said, its a lot more likely to be a problem with the sensor - maybe a DHCP lease renewal issue ? (If its something like that, can you hard code its IP address ?)

davidgo

Posted 2016-04-25T07:11:56.107

Reputation: 49 152

Asked: 2016-04-25T07:11:56.107

Viewed: 50 times

Active: 2016-04-25T09:47:42.137