Which device is an example of a Layer 2 device?

A switch is an example of a Layer 2 device because it operates at the Data Link Layer of the OSI model. This layer is responsible for node-to-node data transfer and handles addressing through MAC (Media Access Control) addresses. Switches effectively manage and direct traffic within a local area network (LAN) by determining which device to send a data frame based on its MAC address. This process allows for efficient communication between devices in the same network, minimizing collisions and improving bandwidth.

In contrast, routers operate at Layer 3, which involves the Network Layer and manages IP addressing and routing packets between different networks. Firewalls can function at various layers but are typically involved in filtering and monitoring traffic at multiple levels, including Layer 3 and Layer 7, not just Layer 2. Modems, on the other hand, serve to modulate and demodulate signals for data transmission over communication lines, functioning at a different layer altogether, often bridging the physical and data link layers but not exclusively corresponding to Layer 2 operations.