Video narration
When you send a photo, it feels like one tap should move it from your phone to someone else's. Instead, it travels through a hidden chain of jobs. Here's the shift: a network is not one giant mechanism. It is smaller jobs cooperating, each owning one part of the trip. The application layer handles your chat. Presentation and session work are often grouped there, preparing the conversation and keeping it going. Transport manages delivery between devices. Network handles addressing and routing. Data link handles the next local connection. Physical turns the message into signals. As the photo moves down, each layer adds control information. This is called encapsulation. At the other end, the layers remove it as the photo moves back up. The OSI model is a reference guide, not seven devices in every network. Remember: layers make the trip manageable, from app to signal and back.