Protokollstacket

Protokollstacket, also known as the protocol stack or network stack, is a conceptual model used to describe the layers of communication protocols used in computer networking. It is a framework that organizes the various protocols and standards used in network communication into distinct layers, each with specific functions and responsibilities. The most widely recognized model is the Open Systems Interconnection (OSI) model, which consists of seven layers. However, the more commonly used model in practice is the TCP/IP model, which has four layers.

The OSI model, developed by the International Organization for Standardization (ISO), provides a comprehensive framework for understanding network communication. It is organized as follows:

1. Physical Layer: Deals with the transmission and reception of raw bit streams over a physical medium.

2. Data Link Layer: Responsible for node-to-node delivery and error detection and correction.

3. Network Layer: Manages logical addressing and routing of data packets.

4. Transport Layer: Ensures end-to-end communication and error recovery.

5. Session Layer: Establishes, manages, and terminates sessions between applications.

6. Presentation Layer: Translates data between the application layer and the network format.

7. Application Layer: Provides network services directly to end-user applications.

The TCP/IP model, which is the foundation of the internet, is simpler and consists of four layers:

1. Network Interface Layer: Equivalent to the OSI's Physical and Data Link layers, it handles the transmission of data over the physical network.

2. Internet Layer: Corresponds to the OSI's Network layer, it is responsible for logical addressing and routing.

3. Transport Layer: Similar to the OSI's Transport layer, it ensures reliable data transfer.

4. Application Layer: Combines the functions of the OSI's Session, Presentation, and Application layers, providing network services to applications.

Both models help in understanding and troubleshooting network issues by providing a structured approach to network communication. They are essential tools for network engineers and administrators in designing, implementing, and maintaining network systems.