Hierarchical internetworking model

In hierarchical internetworking, computers are organized into a hierarchy, which is like a pyramid. All of the computers are connected to the top of the pyramid, which is like the very top layer. Then, there are other layers of the pyramid that get smaller, with fewer computers. Each layer is responsible for something different, and helps the computers talk to each other. The top layer is responsible for helping computers find each other and talk over long distances, the middle layer helps computers on the same network talk to each other, and the bottom layer helps different kinds of computers talk to each other.