Which protocol is most commonly used to send data across individual links?

The choice of Ethernet as the protocol most commonly used to send data across individual links is accurate because Ethernet is fundamentally designed for local area networking (LAN). It operates at the data link layer (Layer 2) of the OSI model and defines standards for how data packets are formatted and transmitted over various types of networks. Ethernet is widely implemented in both wired and wireless networks, making it the cornerstone of local connectivity.

This protocol allows multiple devices to communicate over a shared medium, effectively managing access to the network through methods such as Carrier Sense Multiple Access with Collision Detection (CSMA/CD). Its robustness and compatibility with many network configurations have made Ethernet the default standard for networking in many environments, from home networks to large enterprise systems.

In contrast, while TCP/IP is essential for internet communication and defines how data is transmitted across different networks, it operates at higher layers (network and transport layers) and is not specifically used for individual link transmission. Similarly, HTTP and FTP are protocols built on top of TCP/IP, primarily for web browsing and file transfer respectively, but they are not focused on the fundamental link-layer transmission that Ethernet provides.