Getting "Ethernet port carrier change" daily and don't know where to start.

[konem]

Hi All,

My customers  are complaining that they're being disconnected from the network on a daily basis.  The disconnect lasts usually from 30 seconds to 5 minutes.  I checked the logs on the MR18 and I'm seeing:

     Ethernet port carrier change - device: wired0, carrier: false

and then, seconds later:

     Ethernet port carrier change - device: wired0, carrier: true

I have no idea what's happening and the help topics aren't very helpful.  Can anyone shed some light as to what I should be looking at here?  Thanks.

[PhilipDAth]

That suggests a physical connectivity issue.

Does your MR18 plug directly into a switch, or does it go via something else like a power injector?

Have you tried plugging it into a different port on the switch?

[konem]

It is plugged directly into a cable modem from the ISP.  I have no documentation as to make/model of the modem but I'll be on site early next week to check it out.

Thanks for the quick reply!

[PhilipDAth]

How is your MR18 getting power?

[konem]

It's getting power via the standard power supply.

[MerakiDave · Accepted solution]

Chances are this is usually a cable issue, so have extra patch cables when you go visit the site.  Open a case with Meraki Support as well, they will be able to access lower level details in the logs that could shed more light on the issue, in case it turns out to not be cabling but as issue on the cable modem itself.  If you have access to the online ISP account, send a reset signal to the cable modem or call their support line to have them also troubleshoot and/or reset the cable modem, or just wait until you're on site and reboot it.  First things first though, I'd start by replacing the patch cable, rebooting the MR18, and rebooting the cable modem, then it's a wait-and-see game while you have Support investigate further.  Good luck.

[konem]

Thank you all for the help here. I checked in at the site and found that someone had replaced the patch cable coming in from the modem. They put one of those thin Cat5E cables in and it was wired with only 4 of the 6 cables! I can't believe that this thing was working with just that kind of connection. Your answers made my job much easier fellas. Thanks again.

[ovel]

What's driving me nuts in this merakis solution is this: "Open a case with Meraki Support as well, they will be able to access lower level details in the logs that could shed more light on the issue"

Why on earth these logs cannot be shown on the web page ? Why all important info about the uplink (error rate, packets sent/received) is just hidden from the network engineers? These error messages in logs remind me classic marketing microsoft bs like "something went wrong".