Which layer accepts messages from the network layer and controls the hardware that actually transmits them?

• A. Data Link Layer
• B. Session Layer
• C. Physical Layer
• D. Application Layer

Answer: (A)

This question tests how data moves from the network layer to actual transmission over the medium. The layer that accepts messages from the network layer and controls the hardware that actually transmits them is the Data Link Layer. It sits between the Network Layer (which handles routing and logical addressing) and the Physical Layer (which turns bits into electrical, optical, or radio signals). The Data Link Layer packages packets from the network layer into frames, adds local addressing, and handles error detection and flow control, while the MAC sublayer governs access to the shared medium and the LLC sublayer manages framing and multiplexing. The Physical Layer does the raw signaling, but it’s the Data Link Layer that prepares the data for transmission and directs how the hardware should transmit it.