OSI Model

The OSI (Open Systems Interconnection) model is a conceptual framework used to understand and implement network protocols in seven layers.

The Seven Layers

Layer 7: Application Layer

The application layer provides network services directly to end-user applications. This includes protocols like HTTP, FTP, SMTP, and DNS.

Layer 6: Presentation Layer

Responsible for data translation, encryption, and compression. It ensures that data sent from one system can be read by another.

Layer 5: Session Layer

Manages sessions between applications, controlling dialogues and synchronization between systems.

Layer 4: Transport Layer

Provides reliable data transfer services to upper layers, including TCP and UDP protocols. Handles segmentation, flow control, and error correction.

Layer 3: Network Layer

Handles logical addressing and routing of data packets across networks. IP operates at this layer.

Layer 2: Data Link Layer

Manages physical addressing (MAC addresses) and controls access to the physical transmission medium. Includes Ethernet and Wi-Fi protocols.

Layer 1: Physical Layer

Deals with the physical transmission of data over network media, including cables, connectors, and voltage levels.

Benefits of the OSI Model

• Standardization: Provides a universal language for networking
• Troubleshooting: Helps isolate problems to specific layers
• Interoperability: Ensures different systems can communicate
• Modularity: Changes in one layer don’t affect others