The Gateway is responsible for extending the communication range to reach remote nodes. It consists of a single board computer augmented with a ZigBee coordinator module. Messages are relayed between the ZigBee network and the internet-connected user transparently and robustly, thanks to the powerful hardware specs and efficient software design incorporated within this unit. Each gateway device controls a number of ZigBee nodes which form a network of their own, and the management software controls all the gateways and their children. This layered architecture makes for a reliable and scalable network.