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WS 12 250 DC Ethernet Errors on only some ports

Posted: Fri Jun 02, 2017 11:32 pm
by jadkins@skynetky.com
So I have a switch I fear is damaged. Ports 1 & 2 will not hold 1 gbps they always shift to 100 mbps. When on 1 gbps they count errors like crazy. Port 1 is an air fiber 5x inbound and port 2 is an air fiber 5x outbound. Port 3 is the Ubnt AC Rocket AP for this site going to a sector. I could not even login to the AP today because the errors. I selected another never used random port, I choose port 7 and now it works flawlessly. I have changed the cables going up the tower three times and grounded the rack and chassis of the switch to earth ground going outside to a ground rod. This ground also feeds the AC panel in the building it is an 8 awg bare copper. I installed a lug on it with a 10 awg coming to my rack.

The tower is leased and I do not see a visible ground on it unless it was embedded in the concrete base. Could this damage be due to a potential shift? Whould is cause this behavior? I would like to get 1 gbps here because the inbound bandwidth is well over 200 mbps and I need it because the link stays nears 100 mbps.

Thanks

Re: WS 12 250 DC Ethernet Errors on only some ports

Posted: Sat Jun 03, 2017 11:18 am
by sirhc
Yes ground current can cause limited damage like this and more more extensive damage.
I WOULD BE VERY CONCERNED ABOUT GROUND CURRENT HERE AS YOU BASICALLY ARE SAYING THERE IS NO BOND BETWEEN THE TOWER AND THE ELECTRICAL SERVICE EARTH GROUND. - VERY BAD.

Without that bond your ethernet cable is the bond.

At the very least run a #2 from the service ground to the tower and bind it. You need a GOOD electrical connection from the #2 wire to bare steel not to the painted steel. Options would be CAD weld, or grind the paint off and make the connection with a lug with anti corrosion paste and then paint and seal over connection to prevent rust.

I would bench test the switch as explained here: viewtopic.php?f=6&t=2780

I would find out about the tower grounding system

Here is crib note on grounding things to do: viewtopic.php?f=30&t=2786&p=19279#p19279

Here are some good posts on grounding:
viewtopic.php?f=30&t=1816
viewtopic.php?f=30&t=188
viewtopic.php?f=17&t=1786&start=30#p13447
viewtopic.php?f=30&t=1429
https://community.ubnt.com/t5/airFiber/ ... rue#M31070

Also be aware MANY people including me have had issues with AFX radios constantly jumping down to 1G which is normally related to the physical ethernet jack used in the AFX radios. You can search the UBNT forums for those post and read what people did to work around it.