Which sublayer communicates between the networking software at the upper layers and the device hardware at the lower layers?

• A. LLC sublayer
• B. Network sublayer
• C. MAC sublayer
• D. Physical sublayer

Answer: (C)

The key idea is that the MAC sublayer is the part of the data link layer that directly interfaces with the hardware and medium. It sits right between the upper-layer software that creates and processes frames and the physical layer that actually puts bits on the wire. The MAC sublayer handles access to the shared medium, frames the data with MAC addresses, and enforces the medium access method, so it is the bridge linking software at the upper layers with the device hardware at the lower layers. The LLC sublayer, by contrast, focuses on linking multiple network protocols to the data link layer and provides logical framing and multiplexing, not direct hardware interfacing.