LibreELEC startup with LAN excludes WLAN

Question

When the RPi (with LibreELEC) is connected to the web via WLAN, plugging also the Ethernet cable for wired LAN does not affect the WLAN functionality: it automatically connects to the web via LAN (which is faster) but leaves the WLAN connected to the router even without connection (the WLAN shows ready as status). That for me is very comfortable because I can continue to command it remotely.

When the LAN cable is plugged from the beginning, the WLAN is excluded since the RPi starts up even without connecting to the router (idle status). In the LE settings, both connections are enabled to connect automatically.

I would like to be able to connect both via WLAN and wired LAN even when the RPi is connected via Ethernet from the moment it starts up.

My configuration is an RPi 1 model B with USB-WiFi radio TP-LINK TL-WN725N. LEversion 8.2.5.

Answer 1

Connecting two interfaces eth0 and wlan0 to the same router is possible. They will get different ip addresses from the same subnet they are connected to if you use a DHCP server on your network. But it can only one connection to the router be used. If you plug in the ethernet cable the kernel switches to it and the source ip address of the connection will also switch. This is not a problem for the kernel but any stateful connection will break because of the changed source ip address. Any remote server serving a session connection to the RasPi will send its responses to the old ip address. For example a ssh connection and other login sessions will get stuck and audio/video streams will break.

To avoid this you need a typical failover configuration that does not switch the source ip address. You can use bonding to achieve this. How to setup it you can look at Howto migrate from networking to systemd-networkd with dynamic failover.