Explain the OSI model in computer networking.

The OSI (Open Systems Interconnection) model is a conceptual framework that standardizes the functions of a network into seven distinct layers. Each layer serves a specific role in the process of communication between networked systems. Here’s a brief overview of each layer:

1. **Physical Layer**: Deals with the physical connection between devices, including cables, switches, and the electrical signals used for data transmission.

2. **Data Link Layer**: Manages error detection and correction, and controls data flow between adjacent network nodes. It packages raw bits from the Physical Layer into frames and handles MAC (Media Access Control) addresses.

3. **Network Layer**: Handles routing of data packets across different networks and manages logical addressing (e.g., IP addresses). It determines the best path for data to travel from source to destination.

4. **Transport Layer**: Ensures reliable data transfer between end systems by managing flow control, error detection, and retransmission. Common protocols include TCP (Transmission Control Protocol) and UDP (User Datagram Protocol).

5. **Session Layer**: Manages sessions or connections between applications, handling the establishment, maintenance, and termination of these connections.

6. **Presentation Layer**: Translates data between the application layer and the network format, handling data encryption, decryption, and translation between different data formats or character sets.

7. **Application Layer**: Provides network services directly to user applications. It encompasses high-level protocols like HTTP, FTP, and SMTP, enabling applications to communicate over the network.

The OSI model helps in understanding and designing network protocols by breaking down network communication into manageable, modular components.