OSI and TCP/IP model overview

In order to describe the functionality of the network, including communication between computers, a layered model is used. These layers facilitate the operating system's work whenever the computer is required to communicate with other computers. This concept dates back to the 1960s, known as the time of internet development. It consisted of two protocols, IP and TCP. At that time, the layered framework called the TCP/IP reference model was designed so that later on, it had set the standard of networking functionality on the internet, enabling computers to communicate through a layered format.

To understand the layered model, let's get familiar with the following concepts:

• The protocol suite is a communication protocol stack that is comprised of a set of communications protocols. Some of the most well-known protocol suites in the history of telecommunications and computer networks are IPX/SPX, X.25, AppleTalk, and TCP/IP.
• The reference model is a conceptual model that describes what is occurring in each communication layer without giving any description of how that should be accomplished. The most popular reference model is OSI, which is also a protocol model for the OSI protocol suite.
• The protocol model is a layered model that describes the protocol functions that are taking place at each layer. Since this model matches the structure of a particular protocol suite, TCP/IP is the most popular protocol model that is also used as a reference model.