Odd Ethernet issue

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SirHumphreyAppleby

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#306573 4-Aug-2023 15:15

I have recently obtained five Odroid N2+ units to replace the television front ends (previously a Vero4k and cheap boxes from China with similar hardware). I am experiencing an issue with one of the Odroid boxes, where no link is showing up when connected directly to a secondary switch - no lights on either the Odroid or the switch. I've tried three switches and two cables, with the same result. If I connect it to another port in the house (directly to the main switch), it either negotiates a 100Mbs^-1 or 1000Mbs^-1 connection, depending on the port it is connected to. The wiring is a bit dodgy where it negotiates 100Mbs^1, but other players have no trouble negotiating 1000Mbs^-1 even on that port. Disabling auto-negotiation and forcing it to 1000Mbs^-1 resulted in an unusable connection.

I'm not terribly familiar with how auto-negotiation works, but I assume it is only point-to-point and doesn't look at the network beyond the first switch. Assuming that is the case, there does appear to be a fault with the unit, but I'm also concerned with the RMA process and being told it's working perfectly fine, which under some configurations at least, it does seem to be.

Does anyone have any thoughts on what could be causing this?

Dynamic

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#3111864 4-Aug-2023 18:44

Swap some stuff around. Does the fault stay with a device, a cable, or a port?

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SirHumphreyAppleby

2826 posts

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#3111866 4-Aug-2023 18:49

Dynamic:

Swap some stuff around. Does the fault stay with a device, a cable, or a port?

The device appears to be the only common factor. A second Odroid connected in the exact same way, to the same switch/port and same uplink port to the main switch, works just fine. Yes, I also tried different cables and ports.

The unit which was giving me trouble is now installed in another room and is working as expected. If not for the fact that it gave me trouble in two other locations, I wouldn't have any reason to expect an issue, at least not yet. I've been monitoring it all afternoon, and it's still connected at 1000Mbs^-1.

BarTender

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#3111879 4-Aug-2023 19:36

Odroid hardkernep make excellent hardware I have a few C2s that have been running flawlessly for years. I would see if you can hook up a console cable and see what is coming through on the logs. Helps if you have some Linux experience to help debug it. But I would try a different distro such as Armbian just in case it’s something wonky with the build you have installed.

SirHumphreyAppleby

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#3112102 5-Aug-2023 17:10

Hmm. The box I swapped the problematic one with was working fine, right up until I mounted it behind the television, at which point it started exhibiting the same behaviour... no Ethernet connection. Not even brief flash on boot. It's as if there is nothing plugged in at all.

I tried swapping power supplies, since that was the only remaining common variable, but still no go. I eventually 'solved' the problem with a new Ethernet cable, but I know that's not the underlying cause as that cable wasn't used for earlier testing and another which was, was working fine when the units were swapped around.

I am wondering if there is perhaps a high level of noise on the power line. My Ethernet over power adaptors started acting a bit flakey a few months ago, but seemed to work okay if they were on another circuit.