I may have multiple issues at this site. I get FCS errors on ether8 24 hours per day, but not all the time. The most immediate problem is the inability to operate at 1 Gbps on ether8 in the afternoon.

I don't know what is causing ether8 on one of my units to drop connection and renegotiate at 100Mbps around 2 pm +/- an hour on sunny days. I am beginning to suspect that it could be heat related. We usually catch the problem within a couple of hours. Disabling ether8 then re-enabling it causes it to renegotiate at 1Gbps. I will work on writing a script to check every 10 minutes and bounce ether8 if it is at 100Mbps, after I finish this message.

I am not saying heat is the cause. I am asking if anyone else sees something similar. I am chasing leads, not laying blame. We plan to vent the box to cool it down as part of our investigation.

I have three CCR1009-8G-1S-1S+PC units in the field as base of tower routers. That's not enough units for a statistical sample. I need help from the experience of others running similar routers.

The CCR1009 at this tower location has been installed for less than 2 months. It hasn't seen warm days before the past couple of weeks. We've been looking into FCS errors showing on ether8 since it was installed. The other device connected to ether8 is an AirFiber24 connected 50+ meters of Cat5E away, 75% of the way to the top of the tower.

We've replaced the cable and checked our grounding but the last couple of weeks things have gotten worse with the ethernet renegotiating at 100Mbps in the afternoon. We normally push 400+mbps through this link.

When it happened this weekend, I caught it more quickly than usual. It wouldn't renegotiate above 100Mbps the first few times I bounced ether8. So, I went onsite to look at the problem, 10 minute drive. I noticed that the air in the box was very warm as I opened the door. I left the cabinet door open and visually checked the connections then unplugged the cable from ether8 and plugged it back in. It negotiated at 1Gbps.

When I got back to the house I looked at the temperature graphs of the CCR1009. Most recent values on the left. The problem occurred Monday, Friday, Saturday, and Sunday for the time period covered by this graph. The Sunday peak is 55C. The Saturday peak is 60C. The box is pretty well shaded until 1 or 2 pm. It then gets pretty direct sunlight for about one to two hours.

That's the CPU temp. The board temp shows 10 C lower at the moment.

i have the same device, with similar temperatures, no problem at all

some users of the forum have reported ethernet negotiation problems with airfiber 24

maybe try with eth7, eth8 have poe input capabilities maybe that's the issue

to improve temperatures

try underclocking to 400mhz the device to lower a little the temperatures

or try a little fan inside the cabinet without opening to the exterior to improve the convection between the CCR and the cabinet

Thank you for the feedback.

I have three AF24 links. This is the one ethernet of 6 giving me issues. It is also the longest cable so that may have something to do with it.

Good thought on the "PoE in" being a difference between ether8 and all other ports. I think I will reconfigure to use ether5, since it is currently available, and see what happens there.

I did clock it down to 800MHz last night. I'm pretty sure it requires a reboot after changing clock speed so I did that during the maintenance window. It's been a cooler day today. The highest I've seen CPU temp is 54C. No speed issues today, so far.

Our same router often switches to 100Mbps.
We used wires (10G Ethernet RJ45 CAT6A SFTP Patchcord Cable 0.5M LSOH), so we thought that wires are not a problem. We changed the ports and even the end routers. Some ports end router are burnt out.
And only when the wires were replaced (self-made), everything was solved.
I do not know what the manufacturers in China or elsewhere make in the wires, possibly aluminum, but after a while they are no longer working well.