It solve the issue that ER5120 will hang when I use nmap to scan the router. After upgrade it, everything works normally.

Do you mean ER5120 V2 beta? I ever got a beta from TP-Link. You can have a try. Download link is https://we.tl/t-NFBERTMgI2

I think AC50 could work as a switch. You can think that AC50 is a switch that has CAP controller function.

@hamedfazel You have multiple public IP address. So you have used multiple WAN ports, or one WAN port has multiple public IP address? If one WAN port has multiple public IP, did you achieve that with...

I think you need to confirm with your ISP, which dialup mode need to be set. For example, your ISP uses PPPoE, then ER6020 need to use PPPoE for WAN when your modem is bridge mode. When you make the...

EAP controller supports to send system log to your email. But seemly cannot send realtime alert email when EAP go offline. Hope TP-Link can add this feature in the future.