The Z-Wave protocol is a low bandwidth half-duplex protocol designed for reliable and robust wireless communication in a low cost control mesh network. The protocols main purpose is to communicate short control messages in a reliable manner from a control unit to one or more nodes in the network. The protocol is not designed to transfer large amounts of data or to transfer any kind of streaming or timing critical data. The protocol consist of 4 layers， the MAC Layer that controls the RF media， the Transfer Layer that handles frame integrity checks， acknowledgements， and retransmissions， the Routing Layer that controls the routing of frames in the network and application interface; and finally the Application Layer controls the payload in the transmitted and received frames.