Overview of the OSI Reference Model PDF

## Overview of the OSI Reference Model - The OSI model stands for the Open Systems Interconnection Reference Model and is a communication model for dissimilar machines, developed by the ISO. - It provides a multilayered system of protocols, where protocols interact only with adjacent layers. - Th...

## Overview of the OSI Reference Model - The OSI model stands for the Open Systems Interconnection Reference Model and is a communication model for dissimilar machines, developed by the ISO. - It provides a multilayered system of protocols, where protocols interact only with adjacent layers. - The OSI model specifies how systems communicate across different networks, allowing any protocol adherent to these standards to communicate with others. ## Layers of the OSI Model - The model consists of seven layers: Application, Presentation, Session, Transport, Network, Data Link, and Physical. - Each layer only communicates with the layer directly above and below it. ## Application Layer - The Application layer enables high-level programs to access network services, such as HTTP and FTP. - It is not to be confused with application software; rather, it serves as a function call interface for applications like web browsers to communicate over the network. ## Presentation Layer - This layer handles data representation, including formats such as JPEG and GIF, encryption, and compression. - It acts as an interface between raw data and application-level functions, formatting data to be correctly interpreted by applications. ## Session Layer - The Session layer manages communication sessions and synchronizes data flow between machines. - Protocols like SSL and RPC operate at this layer to maintain continuous data sessions and provide session management. ## Transport Layer - Responsible for end-to-end message integrity, the Transport layer guarantees that messages are delivered in full. - It includes protocols such as TCP and UDP, which manage how messages are broken down and acknowledged during transmission. ## Network Layer - The Network layer determines the best routing path for data packets to reach their destination. - This layer handles addressing protocols, including IP and ICMP, which help facilitate message delivery. ## Data Link Layer - This layer manages error handling, flow control, and physical addressing for data packets. - Protocols like ARP and PPP function at the Data Link layer, preparing packets for physical transmission. ## Physical Layer - The Physical layer transmits the actual bitstream over physical media, which can include wired or wireless connections. - It facilitates the physical transfer of data packets generated by the layers above it to the network medium.