Which device connects hosts on a local area network (LAN) by MAC address?

The device that connects hosts on a local area network (LAN) by MAC address is a switch. Switches operate at the data link layer (Layer 2) of the OSI model and use the MAC addresses of devices to forward data to the appropriate destination. When a switch receives a data packet, it examines the MAC address in the packet's frame to determine which port to send the packet out. This capability allows switches to efficiently manage traffic within a LAN, ensuring that data is only sent to the intended recipient, which reduces unnecessary traffic and enhances network performance.

In contrast, routers operate at the network layer (Layer 3) and direct traffic between different networks based on IP addresses. Hubs, on the other hand, are simpler devices that operate at Layer 1 and broadcast data packets to all connected devices, without regard for MAC addresses, which can lead to increased network congestion. Modems serve a different purpose altogether, as they modulate and demodulate signals for data transmission over telephone lines, cable systems, or satellite connections, facilitating communication between different networks rather than managing LAN traffic.