Deco M4 ethernet ports not operating in Gigabit mode, but in Fast Ethernet mode (100Mbps cap)
I've got 2 M4 units operating in Access Point mode.
I have full fibre 150Mbps broadband to my house, the cable of which plugs into my ISP's modem/router.
My main M4 is connected to the router via ethernet cable, the other ethernet port on the M4 is then connected to a gigabit switch, which then has a few devices connected to it.
It has been working fine for about two years with no issues until the last week. For some reason the other day all ethernet traffic through the M4 was capping out in the 90-95Mbps speed range. WiFi speeds were unaffected.
Restarting the main Deco appeared to have solved it, as after it restarted all data speeds through its ethernet ports were back to normal. I'd hoped it was a one of glitch, but it appears not as the issue has come up again.
What could be putting the ethernet ports of the Deco into Fast Ethernet (100Mbps) mode and is there any setting I could change to stop this happening? I cannot do the QoS change that I've seen in some other posts relating to slow speeds in the M4, as I am operating in Access Point Mode which doesn't offer QoS control.
It had been two years without issue, so I have no clue what's happened. About two weeks prior to the first instance is when I changed from regular ADSL broadband to full fibre with a different ISP, however, that only changed the modem/router I use, nothing changed with the Deco M4. It has always been used in Access Point Mode.
Edit in: Actually, the only thing that changed with the Decos was I upgraded their firmware within the last few weeks. So maybe this is a firmware issue?