When you sign up for home internet, your Internet Service Provider (ISP) usually sends you a brand-new router to plug in. It handles everything, doing double duty as the modem that connects to your internet and the device that provides Wi-Fi and a routing firewall. It's a one-stop-shop solution, designed to make it quick and easy for novices to get up and running. But ISP-provided routers generally suck, and that's why I prefer to buy my own router instead.