Why does my hub cause so many CRC errors?

Title pretty much sums it up. Want to know why my hub is always causing CRC errors.

Autoneg fix is active, so its not a duplex negotiation issue causing it.

Its also not the cable, cable length, or how close the hub is to other devices, Swapping it with any other known good cable of length from 2 feet to 150 feet still results in the errors. I've tried 8 cables now. I have also taken the hub out into my yard with just an extension cord and cat5 over 100 feet from the nearest electronic device, issues still occurs.

Its not the port or device the hub is being connected too, nor is it another device on my network, I have used 2 different switches and 3 different routers, every port on each, crc errors appear wherever the hubitat is connected, with or without other devices connected.

I'll be using wireshark at some point soon to see if I can spot anything unusual. Anything in specific anyone can think of I should look into or try to trace or fix the issue?

Perhaps to rule out a bad NIC try a usb to ethernet adaptor.
I plugged one into my C4 hub and the hub recognized it instantly.
The hub was reachable from both IP addresses.
I cannot remember if I have tried it on my C5 hub yet but a micro USB Y cable with a Nortek USB works so I would imagine the USB to ethernet would work as well.

Where we see most CRC errors coming from is non-compliant cable runs, Not crossing electrical at 90 degrees, running in parallel with electrical, running over ballasts in lighting, motors, etc. Occasionally a bad cable, but rarely a port on the device or the switch unless there was a power surge.

Have you tried a short cable test with the hub to the switch? I have a known good 3 ft patch cable that I use. A good CAT 5e or CAT 6 next to the switch and then run large block transfers to the device. Then run tests.

If one was able to telnet into the Hub this would be the way to do diagnostics in Linux:

I am using all CAT 6 with various lengths with no errors.
C4 hub 3ft CAT 6 connected to 10gbe Netgear switch. Port limited to 100mbps
C5 hub 1ft CAT 6 connected to ASUS Rapture AX router. Port auto-negotiated
C5 hub 6ft CAT connected to Netgear Nighthawk SX10. Port limited to 100mbps.

There is a known auto-negotiation issue with ASUS and Netgear. My USB testing was performed incase I needed a solution for the hub to router config because I am unable to set the port speed on my AX11000 router.
On that network there is not a switch installed capable of setting the port speed. It is a dedicated IP camera network consisting of router and POE switches.

perhaps a soft reset since you do not think itโ€™s hardware.

I do wish that more switch and router vendors would expose the ability to set speed, flow control, power saving, etc. In the past 5 years nobody makes "dumb" switches anymore they just hide the management.

It is still possible to have a bad port but that would always be my last item on the list. What is the CRC error rate on the device? (errors per minute)

Per my post it has been tested with 8 different known good cables, the shortest of which being 2 feet. Its not the cables.

That requires throwing money at the problem, which is kinda what I got the hub to help prevent.

I don't think its my network hardware, I think I got a defective hub. Already done a soft reset twice and a full/hard reset once. Makes no difference so its not DB corruption.

The autoneg fix is applied, and just to make sure it wasn't still an issue with that I have tried locking the port the hub is on to 100 full. Also makes no difference.

Completely random depending on hub activity. If i run through the house triggering all my motion senors, or activate a bunch or routines/rules, or even just issue a few commands i'll see a crc spike. It can be just 1 or 2 errors, or it can be 100 of them in 5 minutes. So far there doesn't seem to be any specific trigger.

Reset my statistics 6 hours ago before going to sleep, in that time there were 671 crc errors from the hub.

Anyone have any other suggestions? Probably should have mentioned I have quite the sordid past with IT, meaning i have a good bit of experience in most fields. I have multiple computers, running every base os (mas windows android, nix) and I do have Pi4 so if there are any nix Diags you want me to run and report back just let me know!