In the previous chapter, we created a static hierarchy of nodes. The IoT Gateway supports a dynamic hierarchy. While the concentrator infrastructure in the gateway performs most of the tasks required to manage your nodes, you need to provide some basic information that the gateway cannot guess. INode defines methods that allow the gateway to understand which node classes can be added where. It asks all available node classes, which it fetches from the inventory, and asks them who can be added to whom, and which nodes accept which nodes as children. If the response is positive to both these questions, the corresponding child type can be added to the corresponding parent type.