What is a characteristic of the LLC sublayer?

• A. It provides the logical addressing required that identifies the device.
• B. It defines software processes that provide services to the physical layer.
• C. It provides delimitation of data according to the physical signaling requirements of the medium.
• D. It places information in the frame allowing multiple Layer 3 protocols to use the same network interface and media.

Answer: (D)

The LLC sublayer provides multiplexing of network-layer protocols over the same data link by placing a protocol identifier in the frame. This lets multiple Layer 3 protocols, such as IPv4 and IPv6, share the same network interface and media without needing separate frames for each one. LLC sits above the MAC sublayer and provides a way for the Network Layer to identify which protocol should process the payload, using protocol identifiers (SAP values).

Logical addressing (IP addresses) is a Network Layer function, not LLC, and the MAC sublayer handles frame delimitation and physical addressing. The LLC’s role is not to define software processes for the physical layer. Because LLC enables multiple Layer 3 protocols to be carried over a single data link, the best fit is that it places information in the frame to support multi-protocol use of the same network interface and media.