ISO Open Systems Interconnection (OSI) model is one of the most widely read about topic in the area of systems connectivity. The OSI layer consists of 7 layers, viz Application, Presentation, Session, Transport, Network, Datalink, and Physical. Each of these layers have been explained in detail. Relationship between OSI model and network devices has been given.

TCP/IP, short for Transmission Control Protocol/ Internet Protocol is the protocol of choice for Internet communications. The article describes layered approach to the protocol stack and relates to the 7-layer OSI protocol.