Although the OSI model provides a conceptual framework for communication between computers, the model itself is not a method of communication. Actual communication is made possible through communication protocols. In the context of data networking, a protocol is a formal set of rules and conventions that governs how computers exchange information over a network medium. A protocol implements the functions of one or more OSI layers. A wide variety of communication protocols exist, but they all tend to fall into one of the following groups: LAN protocols, WAN protocols, network protocols, or routing protocols. LAN protocols operate at the physical and data link layers of the OSI model and define communication over the various LAN media. WAN protocols operate at the lowest three layers of the OSI model and define communication over the various wide-area media. Routing protocols are network layer protocols that are responsible for path determination and traffic switching. Finally, network protocols are the various upper-layer protocols that exist in a given protocol suite.
Many protocol suites specify various protocols defined in the seven OSI layers. Protocol suites are also known as protocol stacks.
Was this article helpful?