Tell me about the OSI model. What levels do you know? What happens at each level?

The OSI (Open Systems Interconnection) model is a reference network model that divides the data transmission process into 7 layers:

1. Physical Layer — transmission of bits over physical channels (cables, radio channels). Defines electrical and mechanical characteristics.

2. Data Link Layer — frames formation, reliable transmission between neighboring nodes, media access control.

3. Network Layer — routing of packets between different networks, path determination.

4. Transport Layer — reliable data transfer between end nodes, flow and error control (e.g., TCP).

5. Session Layer — session management, establishing, maintaining, and terminating connections.

6. Presentation Layer — data transformation, encoding, encryption, compression.

7. Application Layer — interaction with end applications, high-level protocols (HTTP, FTP, SMTP).

Each layer performs its functions and interacts with neighboring layers, ensuring comprehensive data transmission in the network.