Which device operates primarily on the Data Link Layer of the OSI model?

A switch operates primarily on the Data Link Layer of the OSI model, which is the second layer. This layer is responsible for node-to-node data transfer and for error detection and correction that may occur at this layer. Switches use MAC addresses to forward data to the appropriate device within the same local area network (LAN). By functioning on the Data Link Layer, switches can create and maintain a MAC address table that helps them learn which devices are connected to which ports, enabling efficient data transmission and minimizing collisions.

In contrast, routers operate on the Network Layer, which is the third layer, managing traffic between different networks and making decisions based on IP addresses. Hubs, although they serve a role in networking, operate at the Physical Layer and do not analyze or process data, simply transmitting signals to all devices on the network. Firewalls, which are primarily associated with security, can operate at various layers but typically analyze traffic at the Network Layer and above to enforce policies and protect the network. Thus, the switch is distinguished by its role at the Data Link Layer, focusing on local data transmission within a network.