668 ITU‐T's Technical Reports and Specifications Figure 14 – Description structure for the nine‐tuple smart sustainable cities node information 1) Identification information: such information includes keywords and the node name, identity (ID), type, level, and dynamic feature, which describe the general information of a node for uniquely identifying a node. 2) Characteristics information: such information includes node function, suitable fields, core units, platform environment, communication fabric, and input and output features that describe the characteristic information of a node. The core units refer to sensor, processing algorithm, or service to different types of nodes. 3) Capability information: such information includes function, communication, capability, and resource consumption capability features. Heterogeneous nodes have different function capabilities and need to have extended metadata according to a specific node type. 4) Quality information: such information includes product quality and quality of service (QoS) features. Various nodes have different quality indicators and need to have extended product quality metadata according to a specific node type. 5) Space‐time information: such information includes time and space referencing framework, location, and valid time features that describe the real location and time of a node in dynamic observation systems. 6) Working information: such information includes the use state, fault state, and resource consumption, which can determine whether a node is available at a task moment. 7) Service information: such information includes the service name, type, address, parameters, provider, and mode features that describe the metadata contents of node service interfaces. The relation among the services of a service combination can be represented through the service connection feature. 8) Administration information: such information includes contact, history, and document features that note the important information usable for node administration management. 9) Constraint information: such information includes access level, legal constraint and security constraint features, which affect the accessibility of a node.