The MAC address is a Layer 2 identifier used on Ethernet networks. Which OSI layer is it associated with?

• A. Layer 3 identifier used on IP networks
• B. Layer 7 identifier used on applications
• C. Layer 2 identifier used on Ethernet networks
• D. Layer 4 identifier used on TCP

Answer: (C)

MAC addresses function at the data link layer, which is Layer 2 in the OSI model. They identify hardware interfaces on a local Ethernet network and allow switches to forward frames to the correct device within the same LAN. This local, frame-based addressing is distinct from other layers: Layer 3 uses IP addresses for routing packets across networks; Layer 4 uses port numbers for TCP/UDP transport; Layer 7 relates to application-level identifiers. Therefore, the MAC address is best described as a Layer 2 identifier used on Ethernet networks.