Which device operates at the data link layer of the OSI model?

The device that operates at the data link layer of the OSI model is a switch. The data link layer is responsible for establishing, maintaining, and deciding how data transfer is accomplished over the physical layer. It manages the physical addressing (MAC addresses) and allows for error detection and correction during data transmission.

Switches function at this layer by using MAC addresses to forward data to the correct destination within a local area network (LAN). When a switch receives a frame, it examines the MAC address and determines which port to send the data to, thereby directing traffic efficiently and reducing collisions on the network. This capability enhances the overall performance of the network by enabling multiple devices to communicate simultaneously.

Devices like routers operate at the network layer, where they manage data routing between different networks using IP addresses. Firewalls can function at various OSI layers, depending on their design, but they mainly operate at layers 3 (network) and 4 (transport). Hubs, being simpler devices, operate at the physical layer, merely transmitting signals without any filtering or addressing, making them less efficient than switches in managing data traffic. By focusing on data link layer operations, switches serve a critical role in building effective and efficient network topologies.