Networking

The OSI (Open Systems Interconnection) Model is a conceptual framework that standardizes network communication functions into seven logical layers:

1. Physical (Layer 1): Transmits raw bit streams over physical media (cables, fiber, radio frequencies).
2. Data Link (Layer 2): Encapsulates packets into frames and handles node-to-node data transfer, error detection, and MAC addressing (Switches operate here).
3. Network (Layer 3): Routes data packets between different networks using IP addressing (Routers operate here).
4. Transport (Layer 4): Manages end-to-end connection control, reliability, segmenting, and port addressing (TCP/UDP protocols operate here).
5. Session (Layer 5): Manages authentication, session authorization, and continuous dialogue connection control between applications.
6. Presentation (Layer 6): Translates, encrypts, decrypts, and compresses data formats (SSL/TLS, JSON/XML mapping).
7. Application (Layer 7): Provides network interface access to end-user software services (HTTP, DNS, SSH, SMTP).