Which layer of the OSI model does a typical Layer 2 switch primarily operate at?

• A. Data Link layer (Layer 2)
• B. Physical layer (Layer 1)
• C. Network layer (Layer 3)
• D. Transport layer (Layer 4)

Answer: (A)

A Layer 2 switch primarily operates at the Data Link layer because its core job is to forward and filter frames based on MAC addresses. It learns the source MAC addresses on each port to build a MAC address table, then uses that table to send frames only to the appropriate destination port or to flood when the destination is unknown. This frame-focused activity, using MAC addresses and Ethernet framing, is the essence of the Data Link layer. The Physical layer is involved in the actual bits-on-the-wire transmission, but the switch’s intelligence and decision-making sit at Data Link. It does not route between networks, which would be a Network layer function, and it does not handle end-to-end transport protocols like TCP/UDP, which are Transport layer concerns. A typical Layer 2 switch may also support VLANs to segment broadcast domains at the Data Link layer, but its primary role remains frame forwarding based on MAC addresses.