What is a network protocol?

A network protocol is fundamentally defined as a set of rules that govern how data is transmitted and communicated across different devices within a network. These protocols establish standard procedures for data formatting, transmission, error handling, and connection management, ensuring that devices from different manufacturers can communicate effectively and reliably.

Protocols dictate aspects such as how devices identify each other, what methods they use to establish connections, and how data packets are structured and sent across the network. Examples of well-known network protocols include TCP/IP, HTTP, and FTP, each serving specific roles in facilitating various types of communications over the internet or local networks.

The other options describe different concepts that do not align with the established definition of a network protocol. A physical device relates to hardware, such as routers or modems, while software applications that focus on security or malware have distinct purposes separate from establishing communication rules in a network context.