@kujata 

Something similar happened to me yesterday when I discovered my NAS connected to one of the AX55’s LAN ports was only showing a 100 Mbps connection instead of the usual 1000 Mbps.  The connections were as follows:

Main Router (different make) --->  AX55  --->  NAS

The AX55 was configured in AP mode (with Wi-Fi off) and therefore only acting as a switch.  I was only using the AX55 this way because it was “left over” from a previous configuration.  While troubleshooting, I wanted to set the affected port to 1000 Mbps and disable the auto-negotiation, but as you stated, it is not possible in AP mode.  As all the AX55 ports were being used, I decided to swap out the AX55 with a TL-SG108E switch, giving me 3 extra ports for the moment.  After the swap, everything returned to normal and, in fact, everything appears to be faster, especially my PC screen.

From my point of view, something is not quite right with the switching functions of the AX55 even though I couldn’t pinpoint the problem.  Later, when monitoring the switch performance, I found a large number of bad packets but it turns out that the number of bad packets is due to the way the switch chipset counts VLAN packets as bad packets.  I changed the main router’s port from a trunk port to an access port and the bad packets problem went away.  I don’t know if perhaps the VLAN packets passing through the AX55 might have caused the link speed to drop or not.

  @Marvin_S 

Hi, thanks for your reply.

I am talking about the link speed between the AX55 Access Point and the main router - which is connected to the internet.

I check the link speed via the AP control panel.

With the auto negotiation active, sometimes it negotiates 100Mbps - which is correct - and sometimes it negotiates only 10Mbps (I don't know why).

When in Router Mode, it is possible to disable the automatic negotiation via the advanced settings and to set a fixed link speed.

Kind regards,

Davide