2.2. 7-Layer OSI ModelThe open systems interconnection (OSI) model was the original standard description for how messages should be transmitted between any two points. To the five TCP/IP layers, OSI adds the following two layers :
The tasks of these two additional layers are dissolved into the application and transport layers in the newer five-layer model. The OSI model is becoming less popular. TCP/IP is gaining more attention, owing to its stability and its ability to offer a better communication performance. Therefore, this book focuses on the five-layer model. |