Which sublayer enables IPv4 and IPv6 to utilize the same network interface and media?

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

Answer: (D)

The function being tested is how multiple network-layer protocols can ride on the same data-link. The LLC (Logical Link Control) sublayer provides a common interface to the Network layer and uses signaling (like service access points) to identify which network-layer protocol is carried in the payload. That means IPv4 and IPv6 can both use the same network interface and the same media because the LLC layer handles multiplexing between different IP versions over the same link. The MAC sublayer, by contrast, is about getting frames onto the physical medium and coordinating access, as well as hardware addressing; it doesn’t distinguish IPv4 from IPv6. So the capability for both IP versions to share the same link comes from the LLC sublayer.