OSI Model Explained - A Complete Guide to the 7 Layers
What is the OSI Model?
Introduction to the OSI Model
- The video begins with a prompt to subscribe for notifications about new content related to the OSI model.
- The OSI model, which stands for Open System Interconnection, facilitates data transmission between two computers by outlining how data flows and what protocols are involved.
- In simple terms, the OSI model helps understand data flow management and transmission between computers.
Development of the OSI Model
- The OSI model was developed by ISO (International Standard Organization), which created seven layers to describe how data travels from one computer to another.
Layers of the OSI Model
Upper Layers
- The upper three layers—Application, Presentation, and Session—are responsible for creating data.
Lower Layers
- The lower four layers—Transport, Network, Data Link, and Physical—are responsible for sending data.
Functions of Each Layer
Application Layer
- When a computer sends an email, it uses an application protocol like HTTP or FTP to transfer data.
Presentation Layer
- This layer modifies or represents data in a suitable format before transmission. It handles encoding and compression tasks.
Session Layer
- This layer checks if both computers are connected before allowing any data transfer.
Transport Layer
- Responsible for transmitting data using protocols such as TCP (for large files) or UDP (for smaller information). TCP provides reliability through acknowledgments while UDP does not.
Network Layer
- Determines the best path for data transmission using routers as layer 3 devices that manage this process.
Physical Layer Details
- Defines physical connectivity arrangements like topology (e.g., star topology), ensuring proper device arrangement and connection integrity.
Conclusion
- The video concludes with an invitation for viewers to comment on their thoughts or questions regarding the content discussed.