The ZigBee standard specifies three different types of nodes that might be present in a ZigBee network. A coordinator is the only mandatory node type to be present in the network. The coordinator acts as the root node and is responsible for many network management activities including: configuring key networking parameters, network start, admission of other nodes, and network address assignment. Because of high processing power and inability to sleep, the coordinator should be connected to a steady reliable power supply source. Only a full functionality device (FFD) in IEEE 802.15.4 terminology can act as a network coordinator. A node that has IEEE 802.15.4 FFD capability but does not act as network coordinator is called a router. Because routers can associate other nodes in the network as well as route data frames to their destinations, they can be used to extend network coverage area beyond transmission range of a single device and/or to increase network reliability by creating additional data routing paths. Nodes of this type can directly communicate only with a single router or coordinator. Among other node types end devices consume less processing, memory and power resources and usually are deployed on batteries in power saving mode. Therefore ZigBee end devices correspond to reduced functionality devices (RFD) in IEEE 802.15.4 standard.