The EcoStruxure Machine Expert control network is a system programmed to configure itself (address assignment) to support transparent communication media and to route packets between different networks. The routing mechanism is simple enough that any node in the network, that is, even nodes with low resources, are able to reroute packets. So, large routing tables, complex calculations, or requests during runtime are avoided.
The control network is configured hierarchically, that is, each node has one parent node and an arbitrary number of children. A node without a parent is referred to as top-level node. Cycles are not permitted, that is, a control network has a tree structure.
Parent-child relationships arise from the specification of network segments. A network segment corresponds, for example, to a local Ethernet or a serial point-to-point connection. It distinguishes between the main network (mainnet) and the subnetworks (subnet). Each node has, at most, one main network, wherein it expects its parent. For each node, an arbitrary number of subnets can be configured. The node acts as parent for all of them.
If a network segment had been defined simultaneously as subnet of several nodes, the network would have several parents. However, the resulting configuration will be invalid, as each network segment is allowed to have one single parent only.
