OSI Model
Definition
The Open Systems Interconnection (OSI) model is a conceptual model that characterizes and standardizes the communication functions of a telecommunication or computing system without regard to their underlying internal structure and technology. Its goal is the interoperability of diverse communication systems with standard protocols. The model partitions a communication system into seven abstract layers.
Why It Matters
The OSI model provides a standard framework for understanding how network communication works. By breaking the complex process into seven distinct layers, it makes it easier to teach, design, and troubleshoot networks.
Contextual Example
The seven layers are: 7. Application (e.g., HTTP), 6. Presentation, 5. Session, 4. Transport (e.g., TCP), 3. Network (e.g., IP), 2. Data Link (e.g., Ethernet), and 1. Physical (e.g., cables).
Common Misunderstandings
- The OSI model is a conceptual reference model. The TCP/IP model is the actual protocol suite used to implement the internet, and it is simpler, with only four layers.
- Understanding the OSI model is still very important for network engineers as a tool for thinking about and troubleshooting problems.