What is the purpose of a network protocol?

The purpose of a network protocol is to define rules for communication over a network. Protocols establish the guidelines that dictate how data is transmitted and received, ensuring that different devices and systems can understand each other. This includes aspects such as data format, transmission timing, error handling, and how devices establish and terminate connections. By having these standardized rules, devices from different manufacturers can communicate effectively, which is essential for the functionality of any network.

In contrast, the other options do not accurately capture the essence of what a network protocol does. While physical connections for devices are necessary for establishing a network (which involves hardware elements), protocols specifically focus on the rules governing communications. Storing data securely refers to data protection and encryption methods rather than the communication structure itself. Monitoring network performance pertains to analyzing the efficiency and throughput of the network but does not define how devices communicate according to established protocols. Thus, defining rules for communication is the clear and precise role of network protocols.