The document discusses standards and standardization bodies for Internet of Things (IoT) systems. The Internet Engineering Task Force (IETF), International Telecommunication Union (ITU-T), European Telecommunication Standards Institute (ETSI), and Open Geospatial Consortium (OGC) have all proposed standards and reference models for IoT layers, communication, and device/sensor capabilities. Specifically, ETSI defined domains and capabilities for machine-to-machine communication systems, while IETF, ITU-T, and OGC focused on network layers, transport protocols, and sensor discovery/metadata.