The Open Systems InterConnection (OSI) model is a reference model developed by International Organization for Standardization (ISO) in 1984. Which describes how communication should take place between two nodes in a network.
- Framework design to communicate across all types of computer systems.
- Consists of seven separate but related layers.
- Each layer performs specific functions and then passes result to another layer.
- Each layer defines the process of moving information across a network.
- Request of data moves from top application layer to bottom physical layer and reverse happens at the receiving end.
- Remember its not a protocol but its a model.
- 1. Physical Layer
- 2. Data Link layer
- 3. Network Layer
- 4. Transport Layer
- 5. Session Layer
- 6. Presentation Layer
- 7. Application Layer
Details of each layer is explained in further points of this chapter.
Read this reference model properly, because this will help you in understanding TCP/IP protocol and other networking concepts.