OSI MODEL

OSI model development
Researched and developed by the ISO -  International Organization for Standardizations.
1977: establish a subcommittee to develop a communications architecture.
1984: publish ISO-7498, the Open System Interconnection (OSI) reference model.


                                                  Evolution of networking standards

                                                                                                                                                                                                                          for networking need the Standard

The OSI model: a framework within which networking standards can be developed.

It provided vendors with a set of standards that ensured greater compatibility and interoperability between the various types of network technologies that were produced by the many companies around the world. 

Why a layered model?

Reduces complexity.
Standardizes interfaces.
Facilitates modular engineering.
Ensures interoperable technology.
Accelerates evolution.
Simplifies teaching and learning.



                                                  7 layers of the OSI reference model