The network configuration of a ZigBee network can consist of several radio networks, each controlled separately by a ZigBee coordinator (ZC), the so-called PAN coordinator (Private AreaNetwork). Each individual ZigBee radio network can comprise up to 255 active nodes
. If several radio networks are interconnected, a total of up to 4,000 nodes can communicate with each other. A distinction is made between Full Function Devices (FFD), which are the ZigBee routers, and Reduced Function Devices (RFD), which are the ZigBee end devices. A Full Function Device can send and receive data packets
and forwards thedata packets from the RFD nodes to the PAN coordinator or vice versa. It thus performs routing functions between RFD, FFD devices and PAN coordinator. The Reduced Function Devices
have no routing function, they can receive and send data packets. They form the sensor node and receive control signals or send sensor signals to the network coordinator or to an FFD node, which then forwards them.
. Besides the startopology, ZigBee knows the cluster tree and the mesh network
, a meshed wireless network. The star topology consists of single point-to-point connections between the network coordinator and the end nodes formed by the FFDs and the RFDs. In this configuration, the FFD nodes have no routing because the RFDs are directly connected to the PAN coordinator. In the cluster structure, the FFD nodes route the data packets to the RFD nodes, which may be further away. The mesh network forms a meshed structure where all the nodes are interconnected. One condition is that each node is connected to at least two others. If several ZigBee networks are interconnected, the communication between the individual networks takes place via the PAN coordinators.