Wired Upload Speed Severely Limited

I have DOCSIS 3.1 service from Comcast/Xfinity. I usually get about 42 Mbps upstream.

I have a Dell Precision 3520 that I connect at home to a Dell W15 dock that's connected via USB-C cable. It has a built-in gigabit ethernet adapter that's connected to my network via CAT6 cable to a Ubiquiti UniFi US-8 switch (which connects directly to a UniFi US-48-500 switch in the basement).

I have noticed my upload speed has been limited to 0.8-1.1 Mbps upstream for a little over a week. I'm not sure when exactly the problem surfaced, but I just noticed it over a week ago. If I'm connected via WiFi, things work fine and I get about 40-42 Mbps upstream.

Things tried: changing out the CAT6 cable, rebooting laptop and dock (leaving each off for a while), disabling IPv6, rebooting cable modem, rebooting router (Ubiquiti UniFi Security Gateway Pro) and master switch, etc. I've connected it to another switch in my office with a longer cable, and I still cannot get a faster upstream speed.

Downstream works fine, and it seems to work fine when I hook the ethernet cable directly to the ethernet port on my laptop.

So it seems like it's something to do with the dock. I'm curious if anyone has any suggestions to try to troubleshoot this to resolve it. I'm not aware of any recent firmware updates to the dock.

Thanks!

Nevermind, I solved my own problem. Don't rely on the Dell support website's autodetect driver update feature. Apparently the latest driver wasn't installed. After running the Dell Command | Update app, it updated the driver and all is fine now.

Well I thought that fixed it, but a reboot has put me right back where I was. UGH

Any help would be greatly appreciated.

Since you're on a laptop could you start bypassing gear and go right to the router and see if you're problem persists?

It does. It seems to be a problem with the dock. If I connect directly to my laptop, things are fine. WiFi things are fine too.

I upgraded the WD15 firmware and things worked swell. Next reboot and it was back to slow speeds again.

ericnixmd said:

It does. It seems to be a problem with the dock. If I connect directly to my laptop, things are fine. WiFi things are fine too.

I upgraded the WD15 firmware and things worked swell. Next reboot and it was back to slow speeds again.

Glad you were able to find the culprit. Not sure how to advise from here... possibly downgrading firmware? For sure I'd try to get Dell's input on the matter first and foremost.

I think I found it. I reinstalled the driver, didn't fix it. I disabled a network bridge (not sure how it got created), and things are working fine now. Rebooted and it's still working fine.

What does the network bridge do?