CSS610-8G-2S+ detecting cable problems?

Hardware MikroTik hardware general
1

Hi,

Just re-done my network topology and moved my CSS610 (running 2.14) from one closet to another about 1.5 m away.

Initial setup was like this:

hAP ac3 (ether5) -------(forced PoE)------> CSS610 (ether1)

All was good, no issues noticed.

Recently I purchased a CRS112-8P-4S (running ROS 7.1.1) and changed my setup to something like this:

hAP ac3 (ether5) ---------> CRS112 (ether2) -------( forced PoE )-------> CSS610 (ether1)

Here’s where the troubles start. I can see this in my CSS610’s web interface:
Screenshot 2022-01-24 173422.jpg
What’s the deal with all the detected cable problems? Shorts and opens?! I was running slim cat6A cables between the switches (~2m long) and between CSS610 and some IoT devices (up to 50 cm long), but even after replacing them with some solid S/FTP cable, the reported issues didn’t go away. There are no errors reported on the error tab of CSS610, nor in CRS112 on the ether2 port. Running a cable test on CRS’ ether2 port reveals no problems (“link-ok”). All cables are quality patch cables, nothing “home made”.

Other than the reported cable issues in the web interface, I don’t see any problems communicating with the connected devices, but i’ll perform some more thorough tests.

What’s could be the deal? The only problem I could think of is the proximity of the ethernet cables in CSS610 to mains power cables and/or to the power supplies of the IoT devices, but the distances are relatively small (2m max)

EDIT: removed PoE for CSS610 and used its original power supply. Same status.

2

Try connecting any of the cables to two CSS610 ports or leaving the far end disconnected. If the shorts go away, probably has to do with link partner. I suspect the test is for complete all 4 pair, standard 75Ohm termination, 1G link. Anything else, like 100M, PoE or blown terminations on far end will cause weird results.

Alternatively the detector might be built for longer wires. Ethernet basically operates at 125Mhz and that’s approx 1.5m wavelength in CAT6. Seeing how your faults are at 2 and 3 meters makes me think the detector is at it’s minimum distance limit and can’t differentiate between cable end and fault.

3

I’ve been in touch with Mikrotik’s support and they’ve been able to reproduce the problem, it seems it’s related to having 100 Mbps devices connected to the ports. Waiting for a software update.

4

My Raspberry Pi (100mbps, short cable) also shows as “Short”
Current Installed Version 2.17

5

Yeah, still happened on 2.17 for me too. But I’ve “retired” the unit since, so it doesn’t bug me anymore :smiley: