Hi,
I am connected to my internet router and my satelite set-top box using TP HomePlugs. My desktop computer is on the first floor, while my router and set-top box are on the ground floor.
Sometimes I loose connection to my router, but not my set-top box. The ethernet interface still works, but ping and packets are not travelling to my router. In such cases I have to wait to see if the problem solves itself, or I have to reset the HomePlug connected to my internet router.

My internet router also has wireless capability, and so I'm using a D-Link DWA-140 USB stick to connect to it using the wireless connection.

I was thinking of using the bonding function in Linux to try to solve this problem by bonding my ethernet and wireless interface. But it seems to me that this will only work if the ethernet interface is physically stopping (or is being disconnected).

So: Is there anyone who can point me in any direction which could help me with my problem ?
If I ping a certain host on the internet and this host is not responding (it's a name server belonging to a central Internet provider in my country so it's not very likely that it will not be available...)
then connection via the TP HomePlug is lost, and I want to use the WiFi-connection.

One way to do this is to delete the default route (which is routed via the ethernet interface) and define it using the wifi-adapter.
Or maybe I could use bonding after all ?

Any solutions or suggestions are welcome.

BTW: I'm using Linux Mint 17.3 with Linux kernel 4.2.0-30. (64-bits).

Here that tells me there's some issue with the network or PC. Did you check TPLink for firmware updates?