The router keeps track of what traffic goes to which actual device on your network. But you can't connect directly to the Internet with just a router. Instead, your router must be plugged into a device that can transmit your digital traffic over whatever type of Internet connection you have.

The simple way to think about routers—especially on your home network—is like this. The router sits in between your Internet connection and your local network. It lets you connect multiple devices to the Internet through one physical Internet connection and also lets those devices communicate with one another over the local network. In addition, the router offers some protection to your devices over being exposed directly to the Internet. To the Internet, all the traffic coming from your house looks like it’s coming from a single device. The router keeps track of what traffic goes to which actual device on your network.