a router connects 2 networks (common AP router/switch is creating a network for your home computers and connecting them to the net) and controls packets between the 2 networks. in this way, the computers on your LAN talk to the router, and the router then talks to the net. never does your computer directly talk to the net. A switch on the other hand forms a DIRECT connection between one computer, and another (that is connected to one of its ports anyways. If you have multiple switched, you will form a daisy chained direct connection, but if the switch connects to a router, well then your just direct connecting with the router.)