This International Standard specifies a method of reliable ‎and secure wireless operation for non-critical monitoring, ‎alerting, supervisory control, open loop control, and closed ‎loop control applications. This standard defines a protocol ‎suite, including system management, gateway considerations, ‎and security specifications, for low-data-rate wireless ‎connectivity with fixed, portable, and slowly-moving ‎devices, often operating under severe energy and power ‎constraints. The application focus of this standard is the ‎performance needs of process automation monitoring and ‎control, where end-to-end communication delays on the ‎order of 100 ms can be tolerated.‎ This standard specifies the following:‎ ‎• physical layer service definition and protocol specification;‎ ‎• data-link layer service definition and protocol ‎specification;‎ ‎• network layer service definition and protocol specification;‎ ‎• transport layer service definition and protocol ‎specification;‎ ‎• application layer service definition and protocol ‎specification, including support for protocol tunneling and ‎gateways;‎ ‎• security and security management;‎ ‎• provisioning and configuration;‎ ‎• network management; and‎ ‎• additive communication role profiles (i.e., one or more can ‎be selected concurrently).‎ Functionality above the application layer of the OSI Basic ‎Reference Model, such as the socalled User Layer and ‎different profiles for functionality at that layer, is not ‎addressed. However, it is discussed briefly in Annex A.‎