Seen this happen before. Has to be a potential between one of the ethernet lines and ground. Sometimes it is because someone used a LV version instead of a HV version.
From: Jaime Solorza Sent: Tuesday, March 31, 2015 11:13 AM To: Animal Farm Subject: Re: [AFMUG] Ethernet Interference from Grounding using GIGE-APC Bring out the Holy Hand ...oops bring out the voltmeter and see what you get. Compare to non affected lines. Ground isolation is a science all to itself Jaime Solorza On Mar 31, 2015 11:04 AM, "Sean Heskett" <[email protected]> wrote: if there is voltage on the ground then yes it will cause ethernet errors. On Tue, Mar 31, 2015 at 10:49 AM, Nate Burke <[email protected]> wrote: I just changed out an ATOM mikrotik to a CCR, and found that it is Incrementing FCS Errors exactly every 30 seconds on the Ethernet line from a Trango LYNX. The lynx is powered via DC, so the Data line is clean of POE. I am using a GIGE-APC Unit on the Ethernet line. What I found through testing, was that the FCS Errors only happened when the GIGE-APC was plugged into the chassis. They happened at exact 30 second intervals. Because of this I'm guessing that there is something introduced via the ground that is causing them. If I pull the GIGE-APC out of the Chassis, the errors stopped, if I plugged it back in, the errors came back, at the exact same clock points (in my CCR Log, always at 06 and 36 seconds regardless of the timing of plugging/unplugging). I'm using the 1U APC chassis, and there are other GIGE-APC, 444APC-HV, and GIGE-POE-APC units in it. None of the other equipment is plugged into the CCR, so unsure if it would increment FCS Errors on those. They are all plugged into RB1100's, and have no errors logged in the mikrotik. Any place to start troubleshooting something like this? Would it make sense that something on the ground plane could cause these Ethernet errors? I believe that this is causing some very low level packetloss through the link, about 1 packet every 5 minutes or so, I'm guessing based on if the ping falls directly on the error frame. Nate
