Internetworking Models
In the very first networks, the computers involved could communicate only with other computers made by the same manufacturer. For example, companies ran either a complete DECnet solution or an IBM solution—not both together. In the late 1970s, the Open Systems Interconnection (OSI) reference model was created by the International Organization for Standardization (ISO) to break through this barrier.
The OSI model was meant to help vendors create interoperable network devices and software in the form of protocols, or standards, so that different vendors’ networks could become compatible and work together. Like world peace, it’ll probably never happen completely, but it’s still a great goal.
The OSI model is the primary architectural model for networks. It describes how data and network information are communicated from an application on one computer through the network media to an application on another computer. The OSI reference model...