This Recommendation specifies common requirements for a smartphone acting as a sink node as well as an end user terminal and a mobile gateway for IoT applications and services. More specifically@ this Recommendation covers: ?C the concept and characteristics of a sink node of the IoT system; ?C work modes of a smartphone as a sink node (SPSN) for IoT applications and services; ?C requirements for the use of a smartphone as a sink node for IoT applications and services.