B5c LAN Speed : 100Mb/s Full Duplex Problem

good day anyone have same problem with my lan speed other devices stack at 1000mbp full duplex but this one has only 100mb full duplex

maybe someone who can help me its almost a week problem

Hi Romel. Welcome to the community.

Let’s start off with the simplest item. Verify that the Ethernet setting in the unit and the switch port aren’t set to 100/Full.

Assuming it’s on automatic or negotiate, the problem is usually somewhere in the Ethernet cabling. Has the unit been installed for a while? If so, was it at 1000 initially? If so, I’ve seen corrosion on the RJ45 jack at the end of the cable cause the problem. This is usually caused by not using dielectric grease on the connector. If that’s not it, then you’ll need to put a cable tester on the Ethernet cable and see if there’s a problem with it (be careful not to damage the tester if it can’t tolerate PoE). The problem could also be inside the PoE injector, if you’re using a separate inline injector.


Hi Wayne2 we already check and try to change the patch cord from poe injector lan port to the engenius poe switch i will also check the configuration if the poe is active were the lan injector connected and try it off. Many thanks


You said you checked the cable between the switch and the injector, how about the cable between the injector and the B5c? This is more likely the cable that will cause a problem.


Had same issue, change poe adapter to another vendor( mikrotik for example) it’s an auto negotiation issue between vendors doesn’t always happens but sometimes betweens ubiquiti switch and mimosa.

Though your problem could be a bad cable or connector but try my suggestion only after you have checked everything.

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