Which OSI layer is typically associated with MAC addressing and Ethernet frames?

• A. Physical Layer (Layer 1)
• B. Network Layer (Layer 3)
• C. Application Layer (Layer 7)
• D. Data Link Layer (Layer 2)

Answer: (D)

MAC addressing and Ethernet frames live at the Data Link Layer because this layer defines how devices on the same local network are identified and how data is packaged for delivery over the physical link. Ethernet frames carry a destination MAC address and a source MAC address in their header, and switches use these addresses to forward frames within a LAN. The Data Link Layer also handles frame delimitation and error detection via mechanisms like the Frame Check Sequence.

The Network Layer handles IP addresses and routing between networks, so MAC addresses aren’t used for end-to-end routing. The Physical Layer is about the actual signaling and bits on the wire, while the Application Layer deals with software processes and user-facing data. For these reasons, MAC addressing and Ethernet frame structure are best associated with the Data Link Layer.