OSI (Open Systems Interconnection) Model

1. Overview

Definition: The OSI Model is a conceptual framework used to understand and implement network protocols in seven layers.
Layers:
1. Physical Layer: Handles the physical connection between devices, including hardware specifications and transmission media.
2. Data Link Layer: Ensures reliable transmission of data frames between nodes within the same network.
3. Network Layer: Manages routing and forwarding of data packets across different networks (e.g., IP).
4. Transport Layer: Provides end-to-end communication services for applications, including error recovery and flow control (e.g., TCP/UDP).
5. Session Layer: Manages sessions and controls dialogs between computers.
6. Presentation Layer: Translates data between the application layer and the network, including data format translation and encryption.
7. Application Layer: Interfaces directly with applications and provides network services to user applications.
Purpose:
- To standardize communication functions of telecommunication and computing systems.
- To facilitate interoperability between diverse communication networks.
Importance:
- Serves as a guide for networking standards and protocols.
- Helps network designers and engineers troubleshoot issues by identifying which layer is relevant to a problem.