Does Power-line Networking require a computer connected to the modem/router to act as a 'server'?

I'm trying to get a basic mental grasp on the idea of Power-line networking. While I understand that other computer can connect to the network by simply plugging their power-line adapters into any electrical outlet, establishing the connection in the power lines is the part I'm still trying to understand.

In my case, a DSL connection comes into the house via the phone jack and goes to a modem/router. I can either connect wirelessly to the router or plug in via Ethernet.

Does a...

Does Power-line Networking require a computer connected to the modem/router to act as a 'server'?

Does Power-line Networking require a computer connected to the modem/router to act as a 'server'?