Which device is primarily used to connect multiple devices on the same local network?

A switch is primarily used to connect multiple devices on the same local network by receiving incoming data packets and redirecting them to their intended destination within that network. It operates at the data link layer (Layer 2) of the OSI model, making decisions based on MAC addresses. This functionality allows devices such as computers, printers, and servers to communicate and share resources efficiently within the same network segment.

In contrast, while a router connects multiple networks and directs data packets between them, its main function is not limited to a single local area network (LAN). A gateway serves as a bridge between different networks, potentially with different protocols, while a modem is used to modulate and demodulate signals for internet access but does not focus on connecting devices within a local network. Thus, in the context of connecting multiple devices within the same local network, a switch is the most appropriate choice.