What is a modem (which is type of "Gateway")

Some service providers, especially those using a fiber network, install a device outside the home to modulate/demodulate the internet signal before it enters the home. That device is often called an Optical Network Terminal (ONT). In that case, the line coming into the home does not need an additional modem to translate the line. With Winston, your network in this case will be set up as Wall Jack -> WINSTON -> Router -> Computers and other Devices.  

What is a router

A router is a device that connects your devices to one another by creating a Local Area Network (LAN), managing the traffic between the devices, and assigning a local IP address to those devices. By doing so, your devices can share files and other peripherals like hard drives or printers. Most routers have WiFi capabilities, so those devices don't need to be hardwired to the router to have access to the LAN. In addition, routers create a firewall to provide additional security for the devices in the LAN.

Most people connect a router to a modem, so the devices on the router's LAN all have access to the internet.

What is a combination, or all-in-one, modem/router?

An all-in-one modem/router combines the functionality of both a modem and a router. Currently, Winston is not intended for use with only a combination device, and most users will want to also get a standalone router. More information is available here:

Using an All-In-One Modem/Router with Winston