U4 - Sub-optimal ethernet connection rate

Grumpy_Geoff · Post by **Grumpy_Geoff** » Fri Mar 06, 2020 12:16

Any reason you can think of as to why my U4 is connecting at 100 Mbps instead of 1000 Mbps?

If I look in /var/log/messages I see the U4 gets 100 Mbps -
beyonwizu4 user.info kernel: bcmgenet f0b00000.ethernet eth0: Link is Up - 100Mbps/Full - flow control rx/tx

Whereas the T4 connected into the same switch gets 1000 Mbps -
beyonwizt4 user.info kernel: bcmgenet bcmgenet.0 eth0: link up, 1000 Mbps, full duplex

I've swapped the ethernet cables and the switch ports with the same result.

Thoughts?

prl · Post by **prl** » Fri Mar 06, 2020 12:43

When I had that it was a lost connection in the back of the Ethernet RJ-45 socket in the wall plate. Missing connection = 2 usable pairs instead of 4 usable pairs = 100Mb/s max.

peteru · Post by **peteru** » Fri Mar 06, 2020 16:55

Almost certainly bad cabling or a faulty connector somewhere. Quite a few BIOSes on laptops and desktops sold in the last decade have Ethernet test tools that will identify the nature of the cable fault and often provide an approximate distance of the problem.

Grumpy_Geoff · Post by **Grumpy_Geoff** » Fri Mar 06, 2020 17:53

It must be the U4's ethernet port. I've swapped switches and cables with the same result.

Paul_oz53 · Post by **Paul_oz53** » Fri Mar 06, 2020 17:59

Grumpy_Geoff wrote: ↑
Fri Mar 06, 2020 17:53
It must be the U4's ethernet port. I've swapped switches and cables with the same result.

I agree - possibly the port itself or a dry solder joint.