Often related with computer networking, two standard models are discussed. One is TCP/IP model (Transmission Control Protocol / Internet Protocol) and other is OSI model (Open Systems Interconnection). The OSI model was developed by the International Organization of Standardization (ISO) and the TCP/IP model was with the US Defense Advanced Research Projects Agency (DARPA).
Development of TCP/IP model and OSI model were started during early 1970s. TCP/IP model and OSI model were evolved during 1980s. As we have already discussed, TCP/IP is the protocol suite on which almost all of the world’s computer networks run. OSI model couldn’t compete with TCP/IP model, and failed in getting wider acceptance. One of the main reasons behind the failure of OSI model and wider acceptance of TCP/IP model was because big global networks like internet started running on TCP/IP protocol suite. All leading vendors discarded their proprietary networking protocols in favor of TCP/IP protocol suite.
Even now we refer OSI model terminologies while discussing about networking related topics. OSI model clearly explained, how different functions of computer networking should work together. The functions of different layers are clearly defined in OSI model. Universities, colleges and networking training institutes explained the concepts of computer networking based on the terminologies from OSI model for many decades.
For example, while discussing about IP addresses, we also call IP addresses as layer 3 addresses. IP addresses are also called as layer 3 addresses, because IP addresses are linked with the function of layer 3 of OSI model.
As a networking student, you need to understand that OSI model is not being implemented as a software product or as a service these days. But, OSI model explains about the functions of different components of computer networking in a simpler and easier way. The terminologies of OSI model are still used to teach and explain computer networking. You may never ever work on an implementation of OSI model in future, but the legacy of OSI model still continues.