Ok, so i've finally decided to expand upon the Networking models, i slightly touched upon why we use them and what they are. In this blog i'm going to explain each layer in the OSI model , TCP/IP model.

tHE OSI MODEL

Ok, so i'm going to try explain this to the best of my ability whilst trying to make sense. The OSI (Open System Interconnection) model is conceptual so it's like a guide on how each device talks to each other over a network. Each layer serves a specific purpose and interacts with the layers directly above and below it.

  1. Physical Layer:  The physical layer is about the actual physical connections between devices. It includes things like cables and the electrical signals that carry data.
  2. Data Link Layer: This layer sets up and ends connections between two directly connected devices. It also fixes errors from the physical layer.
  3. Network Layer: The network layer decides how data is sent and received across different networks. It uses IP addresses to make sure data gets to the right place.
  4. Transport Layer: The transport layer is about moving data. It ensures data is sent correctly, fixes errors, and controls the flow of data.
  5. Session Layer: The session layer manages sessions between applications. It starts, keeps track of, and ends connections, ensuring data exchange is accurate.
  6. Presentation Layer:  This layer changes data into the right format for the application and network. It also handles data encryption (security) and compression.
  7. Application Layer: The application layer is the one users interact with. It includes services like email, file transfer, and web browsing.

TCP/IP  Model

The TCP/IP (Transmission Control Protocol/Internet Protocol) model is simpler and more commonly used than the OSI model. It has four layers that match up roughly with the OSI model's layers.

  1. Network Interface Layer: This layer deals with the hardware and physical transmission of data, like cables and network cards. It's similar to the OSI model's physical and data link layers.
  2. Internet Layer: The internet layer manages logical addressing and routing. It uses IP addresses to make sure data packets get sent across networks, similar to the OSI's network layer.
  3. Layer 3: Transport Layer:  The transport layer handles data transfer, error correction, and flow control. It uses protocols like TCP and UDP, matching the OSI's transport layer.
  4. Layer 4: Application Layer: The application layer in TCP/IP combines the OSI's session, presentation, and application layers. It manages high-level protocols and provides services like web browsing, email, and file transfer.