Gigabit link defaults to 100Mbit

Single Board Computers Odroid N2/N2Plus/C4
1

Not sure how I can fix this, but my N2 seems to always negotiate at 100Mbit rather than a gig, even though it’s plugged into a gigabit switch.

If I disconnect the cable and reattach and run “ethtool eth0 | grep -i speed” it then confirms 1000Mbit, ie. a gig.

Anyone know why this might be?

I have no issues with other devices on my network all negotiating a gig connection successfully.

2

Oh, I can also run:

ethtool -s eth0 speed 1000 duplex full autoneg off

And that solves the issue but only temporarily, ie. a reboot loses it. Does anyone know how I can make that permanent?

3

I would first try changing to a known good Cat5e/Cat6 cable, just in case the present cable is breaking down in use.

4

Have already tried changing the cable and the port on the wall and the socket on the switch at other end!

For now I have added an autostart.sh bash script and that solves the issue.

6

Sounds like a bad termination of one of your plugs.

7

@anon88919003 I tried multiple cables (different brands) different sockets on the wall and different socket on the switch at the other end!

8

@saroujs You can put it in /storage/.config/autostart.sh

I just used the ethtool tool to force gigabit and full duplex etc. A quick google search will give you the answer.

9

Did You try the direct connect without the wall socket ?

10

That would involve taking my odroid n2 into my loft! So no, I didn’t try that.

11

Maybe the wall socket causing the issue.

12

That’s also what I am thinking.

I have some background in networking and 99% of the time it is poor termination at the sockets that causes this, have you tried an ethernet tester to make sure a signal is coming down all 4 pairs?

13

And I have a cable tester that confirms all pairs are terminated.

14

Also, if I force it to connect at a gigabit I see no issues playing anything back.

15

I’m out of ideas then other than it being a switch issue.

There is nothing that we can change in the OS as gigabit already works otherwise we would of heard more about this from our 2000+ N2 users.

16

It is a negotiation issue with the switch most likely (obviously). I had to replace my managed switch probably 3-4 months ago and went for a cheaper non-managed version as I don’t do vlans etc. so maybe it’s just not a very good switch!

Like I said, I see no issues forcing it to a gig so I suspect my cabling is fine.