Ethernet constantly disconnects

All of a sudden, with no notable computer changes, I am getting constant ethernet disconnects. It continuously disconnects the ethernet for about 3 seconds and then reconnects for one second. This cycle never stops, which completely disables all connectivity for the computer.

I have the UD3900H usb 3.0 conected to an HP laptop and two monitors, along with some USB devices. This installation has been stable for at least a year, and is suddenly a problem.

I have checked the ethernet cables and switches, which are not a problem. I rebooted the router. I disabled and re-enabled the ethernet adapter, which did nothing. I disabled the wifi adapter, which also had no effect on the ethernet disconnects. I ensured I have the latest displaylink drivers from your website, and that did not help.

Network traffic is fine over wifi when I disable the ethernet adapter. Obviously, this is not ideal.

Please help. This is very frustrating.

Hi,

Thanks for reaching out to us, I am sorry this is not working as expected and I am happy to help!

Based on your description of the networking disconnections, our first step is to reset the docking station and computer to see if this helps to restore the functionality, please perform the following:

  1. Disconnect the docking station from the computer and remove the power connection from the back of the docking station, unplug all USB devices from the docking station
  2. Disconnect the docking station’s power supply from the wall and let both the docking station and power supply sit for 30-90 seconds to fully discharge
  3. Restart the computer: In Windows 10: Start -> ( Power Icon ) -> Restart
  4. After 30-90 seconds, reconnect the power supply to the wall socket or power strip
  5. Reconnect the power supply to the docking station
  • verify the blue power LED is illuminated on the front of the docking station, please let me know if this does not come on
  1. Reconnect the docking station to the computer, please verify the USB cables are fully seated on both the docking station and the computer
  • check for the external displays to be detected on the system, if they are not detected please restart the system and let me know if they are not detected after the restart
  1. Reconnect USB devices to the docking station one at a time, test each device to make sure it is working before connecting the next device.

Please let me know if this helps, if not we can go from here.

Thank you,

Pat
Plugable Technology
support@plugable.com

Thank you so much for the quick reply. Unfortunately those steps did not help. What next?

Hi,

Thanks for trying the full reset, I am sorry the issue is still occurring.

Were any new devices added to the network, for example an IP Phone system or new networking hardware ( switches, routers, hubs etc )?

You mentioned rechecking the Ethernet cable, was this done by connecting the cable to the laptop’s built-in Ethernet port or to another system ( using the same connection on the switch or wall port )?

Is it possible to connect the docking station to another computer, and install the DisplayLink software ( https://plugable.com/drivers/displaylink ) then see if the network is stable from the alternate host computer? This will help to narrow down if the problem is being caused on or by the host computer, or if it follows the docking station.

Thank you,

Pat
Plugable Technology
support@plugable.com

Thank you once again, Pat. After extensive troubleshooting, I think I have fixed the problem. I was having the same problem using the dock connected to another computer. I tried different cables and still no help. I tried bypassing the network switch that had been in place for a long time, and that did it. Somehow the switch went bad, but none of the other devices connected to that switch were having any problems. Only the plugable hub was having difficulty, and it didn’t matter which port on the switch I tried. I’m still not sure exactly why that was happening, but I swapped out the switch and it seems to be working now. Thanks for your speedy help. Have you ever heard of strange interactions between the hub and particular networking devices?

Hi,

Thanks for letting me know you found a solution. The DisplayLink DL-3900 chipset that controls the Ethernet port in this docking station is a little bit more sensitive than most computer’s native Ethernet controllers. While controller in a computer will try to compensate for a poor connection or limited connectivity the docking station will also try but it is generally less successful. The docking station also doesn’t support half-duplex modes, so many of the fall back modes when the switch is in trouble may cause poor or no connection for the dock, while other hardware just reduces speed and may increase packet retries.

As this is all up and working now, I will go ahead and mark this ticket as closed. Please feel free to open a new thread or contact us directly via email ( support@plugable.com ) if you have any additional questions.

Thank you,

Pat
Plugable Technology
support@plugable.com