What device is used to connect multiple networks together?

The device that is used to connect multiple networks together is a router. Routers are specifically designed to route data between different networks, making them essential for enabling communication between distinct segments of a network or various networks altogether. They can direct data packets to their appropriate destinations based on their IP addresses, ensuring efficient data transfer across interconnected systems.

Routers can also manage traffic between devices on a local network and outside networks, such as the internet, providing functionalities like network address translation (NAT) and firewall protection. This capability distinguishes routers from other devices like switches, which primarily operate within a single local area network (LAN) by connecting multiple devices on that network, or hubs, which do not intelligently route traffic but merely forward packets to all connected devices.

While bridges can connect separate networks and filter traffic between them, routers offer more advanced routing capabilities and are the preferred hardware for connecting distinct networks, managing data transit across more complex infrastructures.