The OSI Model we just looked at is just a reference/logical model. It was designed to describe the functions of the communication system by dividing the communication procedure into smaller and simpler components. But when we talk about the TCP/IP model, it was designed and developed by Department of Defense (DoD) in 1960s and is based on standard protocols. It stands for Transmission Control Protocol/Internet Protocol. The TCP/IP model is a concise version of the OSI model.
A computer network connects two or more devices together to share information and services, including: Documents, Websites, Databases, Music, Printers and faxes, Telephony and videoconferencing, Email and messaging. Network reference models were developed to allow products from different manufacturers to interoperate on a network.
Computer Network is a group of computers connected with each other through wires, optical fibers or optical links so that various devices can interact with each other through a network.