The modern internet is not based on OSI, but on the simpler TCP/IP model. however, the OSI 7-layer model is still widely used, as it helps visualize and communicate how networks operate and help isolate and troubleshoot networking problems. The OSI model is a reference model for how applications can communicate over networks.
At the very top of the OSI Reference Model stack of layers, we find the Application…
Hypertext transfer protocol (HTTP) HTTP uses a message-based model in which a client sends a request message and the server returns a response message.
The HTTP (requests/responses)message consists of one or more headers.