Each such package could by itself be referred to as a message if we narrow our view to a pair of hardware devices communicating to one another, while in the general sense of the internet communication, a number of sequentially arranged packages together form a meaningful message, such as an image, or a web page.
Unlike device communications, where the form of the message data is limited to protocols supported by the type and capabilities of the devices involved (for example in computer networking we have the TCP and UDP protocols, a walkie-talkie would sending radio waves in specific frequency, and a beacon would be flashing Morse code sequences that a person could read), a software can establish more complex and robust data exchange formats.
Those formats would be translated by the sending party in a form deliverable by the underlying hardware, and then decoded by the receiving party from the hardware-specific format to a form conforming to the original protocol established by the communicating software systems.
This higher-level data exchange allows transferring information in a more-human readable form, and also enables usage of software encryption and decryption techniques to make messaging secure.
This standardization allows different software systems, usually created and maintained by separate organizations, and which could be operating on different hardware devices (servers, computers, smart devices or IoT controllers), to participate in realtime data exchange.
The term message exchange pattern has an extended meaning within the Simple Object Access protocol (SOAP).
[2][3] SOAP MEP types include: The ØMQ message queueing library provides so-called sockets (a kind of generalization over the traditional IP and Unix sockets) which require indicating a messaging pattern to be used, and are optimized for each pattern.
While HTTP's primary goal is to deliver web pages and files over the Internet which are targeted for a human end-user, the REST protocol is mostly used for communication between different software systems, and has a key role in the microservices software architecture pattern.