OSI Model

As I’ve been working through AWS, I’ve been learning more about how the OSI (Open System Interconnection) Model works.

• Layer 7: Application
• Layer 6: Presentation
• Layer 5: Session
• Layer 4: Transport
• Layer 3: Network
• Layer 2: Data Link
• Layer 1: Physical

I asked ChatGPT, and here was its response:

The OSI (Open Systems Interconnection) Model is a conceptual framework used to describe the functions of a networking or telecommunications system. It was developed in the late 1970s and early 1980s by the International Organization for Standardization (ISO) to standardize the way different communication systems work together.

The OSI Model is organized into seven layers, each responsible for a specific aspect of data communication. These layers are:

1. 1. Physical Layer (Layer 1): This layer is responsible for the actual physical connection between devices, including the transmission medium (e.g., cables), connectors, and signaling. It deals with the binary transmission of data as electrical, optical, or radio signals.
   2. Data Link Layer (Layer 2): This layer provides reliable data transfer between two directly connected nodes. It is responsible for error detection, error correction, and flow control. Common protocols in this layer are Ethernet, Wi-Fi, and PPP.
   3. Network Layer (Layer 3): This layer is responsible for routing and forwarding data packets between different networks. It deals with logical addressing (IP addresses) and decides the best path for data to reach its destination. The most common protocol used in this layer is the Internet Protocol (IP).
   4. Transport Layer (Layer 4): This layer ensures the reliable delivery of data between two endpoints, providing error checking, flow control, and congestion control. It also handles the segmentation and reassembly of data. The most common protocols used in this layer are the Transmission Control Protocol (TCP) and User Datagram Protocol (UDP).
   5. Session Layer (Layer 5): This layer manages the establishment, maintenance, and termination of communication sessions between applications. It is responsible for synchronizing and coordinating data exchange between applications on different devices.
   6. Presentation Layer (Layer 6): This layer is responsible for data representation, formatting, and encryption/decryption. It translates data between the format used by the application layer and the format used for network communication, ensuring that the data can be properly interpreted by the receiving system.
   7. Application Layer (Layer 7): This is the top layer of the OSI model and is responsible for providing the interface between user applications and network services. Common application layer protocols include HTTP, FTP, and SMTP.

1. Each layer in the OSI Model communicates with the layer above and below it, providing a modular and structured approach to network communication. This model has been widely adopted in the design and troubleshooting of network systems, as it helps to break down complex processes into more manageable components.