Which definition best fits the term protocol in computer networking?

The term "protocol" in computer networking specifically refers to a set of communication rules that dictate how data is transmitted and received over a network. This encompasses the syntax—how the data is formatted and structured—and the semantics—the meaning of the transmitted bits. Protocols ensure that devices on a network can communicate with each other effectively, regardless of their underlying hardware or software configurations.

For instance, protocols like TCP (Transmission Control Protocol) and IP (Internet Protocol) define how data packets are managed and routed over the internet. Without established protocols, there would be confusion and inconsistency in how devices interpret and respond to network messages, leading to communication failures.

The other options provided refer to distinct concepts: user permissions relate to access control rather than communication; data encryption methods focus on securing information rather than transferring it; while connection hardware pertains to the physical components that enable network connectivity but do not define the rules for communication. Thus, the definition of protocol aligns precisely with the concept of communication rules in networking.