The OSI Model - Explained by Example

The OSI (Open Systems Interconnection) model is a seven-layer framework that standardizes how data travels through computer networks, with each layer adding specific headers to data as it moves from the application down to the physical medium: the Application Layer prepares HTTP requests, the Presentation Layer handles encryption, the Session Layer manages session IDs, the Transport Layer breaks data into segments with port numbers, the Network Layer adds IP addresses for routing, the Data Link Layer creates frames with MAC addresses for local delivery, and the Physical Layer transmits raw bits as electrical or radio signals; this layered approach explains why public Wi-Fi is insecure because anyone on the same network can capture unencrypted frames and read the data.