Networking – How to know whether TeamViewer is working over Wifi or over the Internet, when all computers are on wireless home network

In the past, I used to remotely control one laptop from another one using TeamViewer over Wifi (and not the Internet). Both laptops have built in wireless network cards and the connection type used was of ad-hoc type.

Now, I have set up a home wireless network using a DSL cable + Wifi router and both laptops are connected to the Internet at all times wirelessly. in such a scenario, how do I find out whether TeamViewer is working over Wifi from router (I've turned off the ad-hoc connection between both laptops) or if the software is using the Internet connection?

I prefer using it over Wifi so that more Internet bandwidth is available for other devices and also because the Wifi signal is much stronger and will make things faster than if used over the Internet.