Glossary of IoT terms

This article lists some of the common terms used in the IoT articles.

A

Advanced Message Queueing Protocol

One of the messaging protocols that IoT Hub and IoT Central support for communicating with devices.

Learn more

Casing rules: Always Advanced Message Queueing Protocol.

First and subsequent mentions: Depending on the context spell out in full. Otherwise use the abbreviation AMQP.

Abbreviation: AMQP

Applies to: Iot Hub, IoT Central, Device developer

Allocation policy

In the Device Provisioning Service, the allocation policy determines how the service assigns devices to a Linked IoT hub.

Casing rules: Always lowercase.

Applies to: Device Provisioning Service

Attestation mechanism

In the Device Provisioning Service, the attestation mechanism is the method used to confirm a device's identity. The attestation mechanism is configured on an enrollment.

Attestation mechanisms include X.509 certificates, Trusted Platform Modules, and symmetric keys.

Casing rules: Always lowercase.

Applies to: Device Provisioning Service

Automatic deployment

A feature in IoT Edge that configures a target set of IoT Edge devices to run a set of IoT Edge modules. Each deployment continuously ensures that all devices that match its target condition are running the specified set of modules, even when new devices are created or are modified to match the target condition. Each IoT Edge device only receives the highest priority deployment whose target condition it meets.

Learn more

Casing rules: Always lowercase.

Applies to: IoT Edge

Automatic device configuration

A feature of IoT Hub that enables your solution back end to assign desired properties to a set of device twins and report device status using system and custom metrics.

Learn more

Casing rules: Always lowercase.

Applies to: Iot Hub

Automatic device management

A feature of IoT Hub that automates many of the repetitive and complex tasks of managing large device fleets over the entirety of their lifecycles. The feature lets you target a set of devices based on their properties, define a desired configuration, and let IoT Hub update devices whenever they come into scope.

Consists of automatic device configurations and IoT Edge automatic deployments.

Casing rules: Always lowercase.

Applies to: Iot Hub

Azure Certified Device program

Azure Certified Device is a free program that enables you to differentiate, certify, and promote your IoT devices built to run on Azure.

Learn more

Casing rules: Always capitalize as Azure Certified Device.

Applies to: Iot Hub, IoT Central

Azure Digital Twins

A platform as a service (PaaS) offering for creating digital representations of real-world things, places, business processes, and people. Build twin graphs that represent entire environments, and use them to gain insights to drive better products, optimize operations and costs, and create breakthrough customer experiences.

Learn more

Casing rules: Always capitalize when you're referring to the service.

First and subsequent mentions: When you're referring to the service, always spell out in full as Azure Digital Twins.

Example usage: The data in your Azure Digital Twins model can be routed to downstream Azure services for more analytics or storage.

Applies to: Digital Twins

Azure Digital Twins instance

A single instance of the Azure Digital Twins service in a customer's subscription. While Azure Digital Twins refers to the Azure service as a whole, your Azure Digital Twins instance is your individual Azure Digital Twins resource.

Casing rules: Always capitalize the service name.

First and subsequent mentions: Always spell out in full as Azure Digital Twins instance.

Applies to: Digital Twins

Azure IoT Explorer

A tool you can use to view the telemetry the device is sending, work with device properties, and call commands. You can also use the explorer to interact with and test your devices, and to manage IoT Plug and Play devices.

Learn more

Casing rules: Always capitalize as Azure IoT Explorer.

Applies to: Iot Hub, Device developer

Azure IoT Tools

A cross-platform, open-source, Visual Studio Code extension that helps you manage Azure IoT Hub and devices in VS Code. With Azure IoT Tools, IoT developers can easily develop an IoT project in VS Code

Casing rules: Always capitalize as Azure IoT Tools.

Applies to: Iot Hub, IoT Edge, IoT Central, Device developer

Azure IoT device SDKs

These SDKS, available for multiple languages, enable you to create device apps that interact with an IoT hub or an IoT Central application.

Learn more

Casing rules: Always refer to as Azure IoT device SDKs.

First and subsequent mentions: On first mention, always use Azure IoT device SDKs. On subsequent mentions abbreviate to device SDKs.

Example usage: The Azure IoT device SDKs are a set of device client libraries, developer guides, samples, and documentation. The device SDKs help you to programmatically connect devices to Azure IoT services.

Applies to: Iot Hub, IoT Central, Device developer

Azure IoT service SDKs

These SDKs, available for multiple languages, enable you to create back-end apps that interact with an IoT hub.

Learn more

Casing rules: Always refer to as Azure IoT service SDKs.

First and subsequent mentions: On first mention, always use Azure IoT service SDKs. On subsequent mentions abbreviate to service SDKs.

Applies to: Iot Hub

B

Back-end app

In the context of IoT Hub, an app that connects to one of the service-facing endpoints on an IoT hub. For example, a back-end app might retrieve device-to-cloud messages or manage the identity registry. Typically, a back-end app runs in the cloud, but for simplicity many of the tutorials show back-end apps as console apps running on your local development machine.

Casing rules: Always lowercase.

Applies to: Iot Hub

Built-in endpoints

Endpoints built into IoT Hub. For example, every IoT hub includes a built-in endpoint that is Event Hubs-compatible.

Casing rules: Always lowercase.

Applies to: Iot Hub

C

Cloud gateway

A cloud-hosted app that enables connectivity for devices that cannot connect directly to IoT Hub or IoT Central. A cloud gateway is hosted in the cloud in contrast to a field gateway that runs local to your devices. A common use case for a cloud gateway is to implement protocol translation for your devices.

Casing rules: Always lowercase.

Applies to: Iot Hub, IoT Central

Cloud property

A feature in IoT Central that lets your store device metadata in the IoT Central application. Cloud properties are defined in the device template, but aren't part of the device model. Cloud properties are never synchronized with a device.

Casing rules: Always lowercase.

Applies to: IoT Central

Cloud-to-device

Messages sent from an IoT hub to a connected device. Often, these messages are commands that instruct the device to take an action.

Casing rules: Always lowercase.

Abbreviation: Do not use C2D.

Applies to: Iot Hub

Command

A command is defined in an IoT Plug and Play interface to represent a method that can be called on the digital twin. For example, a command to reboot a device. In IoT Central, commands are defined in the device template.

Applies to: Iot Hub, IoT Central, Device developer

Component

In IoT Plug and Play and Azure Digital Twins, components let you build a model interface as an assembly of other interfaces. A device model can combine multiple interfaces as components. For example, a model might include a switch component and thermostat component. Multiple components in a model can also use the same interface type. For example, a model might include two thermostat components.

Casing rules: Always lowercase.

Applies to: Iot Hub, Digital Twins, Device developer

Configuration

In the context of automatic device configuration in IoT Hub, it defines the desired configuration for a set of devices twins and provides a set of metrics to report status and progress.

Casing rules: Always lowercase.

Applies to: Iot Hub

Connection string

Use in your app code to encapsulate the information required to connect to an endpoint. A connection string typically includes the address of the endpoint and security information, but connection string formats vary across services. There are two types of connection string associated with the IoT Hub service:

  • Device connection strings enable devices to connect to the device-facing endpoints on an IoT hub.
  • IoT Hub connection strings enable back-end apps to connect to the service-facing endpoints on an IoT hub.

Casing rules: Always lowercase.

Applies to: Iot Hub, Device developer

Custom endpoints

User-defined endpoints on an IoT hub that deliver messages dispatched by a routing rule. These endpoints connect directly to an event hub, a Service Bus queue, or a Service Bus topic.

Casing rules: Always lowercase.

Applies to: Iot Hub

Custom gateway

Enables connectivity for devices that cannot connect directly to IoT Hub or IoT Central. You can use Azure IoT Edge to build custom gateways that implement custom logic to handle messages, custom protocol conversions, and other processing.

Casing rules: Always lowercase.

Applies to: Iot Hub, IoT Central

D

Default component

All IoT Plug and Play device models have a default component. A simple device model only has a default component - such a model is also known as a no-component device. A more complex model has multiple components nested below the default component.

Casing rules: Always lowercase.

Applies to: Iot Hub, IoT Central, Device developer

Deployment manifest

A JSON document in IoT Edge that contains the configuration data for one or more IoT Edge device module twins.

Casing rules: Always lowercase.

Applies to: IoT Edge, IoT Central

Desired configuration

In the context of a device twin, desired configuration refers to the complete set of properties and metadata in the device twin that should be synchronized with the device.

Casing rules: Always lowercase.

Applies to: Iot Hub

Desired properties

In the context of a device twin, desired properties is a subsection of the device twin that is used with reported properties to synchronize device configuration or condition. Desired properties can only be set by a back-end app and are observed by the device app. IoT Central uses the term writable properties.

Casing rules: Always lowercase.

Applies to: Iot Hub

Device

In the context of IoT, a device is typically a small-scale, standalone computing device that may collect data or control other devices. For example, a device might be an environmental monitoring device, or a controller for the watering and ventilation systems in a greenhouse. The device catalog provides a list of certified devices.

Casing rules: Always lowercase.

Applies to: Iot Hub, IoT Central, IoT Edge, Device Provisioning Service, Device developer

Device Provisioning Service

A helper service for IoT Hub and IoT Central that you use to configure zero-touch device provisioning. With the DPS, you can provision millions of devices in a secure and scalable manner.

Casing rules: Always capitalized as Device Provisioning Service.

First and subsequent mentions: IoT Hub Device Provisioning Service

Abbreviation: DPS

Applies to: Iot Hub, Device Provisioning Service, IoT Central

Device REST API

A REST API you can use on a device to send device-to-cloud messages to an IoT hub, and receive cloud-to-device messages from an IoT hub. Typically, you should use one of the higher-level Azure IoT device SDKs.

Learn more

Casing rules: Always device REST API.

Applies to: Iot Hub

Device app

A device app runs on your device and handles the communication with your IoT hub or IoT Central application. Typically, you use one of the Azure IoT device SDKs when you implement a device app.

Casing rules: Always lowercase.

Applies to: Iot Hub, IoT Central, Device developer

Device builder

The person responsible for creating the code to run on your devices. Device builders typically use one of the Azure IoT device SDKs to implement the device client. A device builder uses a device model and interfaces when implementing code to run on an IoT Plug and Play device.

Casing rules: Always lowercase.

Applies to: Iot Hub, IoT Central, IoT Edge, Device developer

Device identity

A unique identifier assigned to every device registered in the IoT Hub identity registry or in an IoT Central application.

Casing rules: Always lowercase. If you're using the abbreviation, ID is all upper case.

Abbreviation: Device ID

Applies to: Iot Hub, IoT Central

Device management

Device management encompasses the full lifecycle associated with managing the devices in your IoT solution including planning, provisioning, configuring, monitoring, and retiring.

Casing rules: Always lowercase.

Applies to: Iot Hub, IoT Central

Device model

A description, that uses the Digital Twins Definition Language, of the capabilities of a device. Capabilities include telemetry, properties, and commands.

Learn more

Casing rules: Always lowercase.

Applies to: Iot Hub, IoT Central, Device developer, Digital Twins

Device provisioning

The process of adding the initial device data to the stores in your solution. To enable a new device to connect to your hub, you must add a device ID and keys to the IoT Hub identity registry. The Device Provisioning Service can automatically provision devices in an IoT hub or IoT Central application.

Casing rules: Always lowercase.

Applies to: Iot Hub, IoT Central, Device Provisioning Service

Device template

In IoT Central, a device template is a blueprint that defines the characteristics and behaviors of a type of device that connects to your application.

For example, the device template can define the telemetry that a device sends so that IoT Central can create visualizations that use the correct units and data types. A device model is part of the device template.

Casing rules: Always lowercase.

Abbreviation: Avoid abbreviating to template as IoT Central also has application templates.

Applies to: IoT Central

Device twin

A device twin is JSON document that stores device state information such as metadata, configurations, and conditions. IoT Hub persists a device twin for each device that you provision in your IoT hub. Device twins enable you to synchronize device conditions and configurations between the device and the solution back end. You can query device twins to locate specific devices and for the status of long-running operations.

See also Digital twin

Casing rules: Always lowercase.

Applies to: Iot Hub

Device-to-cloud

Refers to messages sent from a connected device to IoT Hub or IoT Central.

Casing rules: Always lowercase.

Abbreviation: Do not use D2C.

Applies to: Iot Hub

Digital Twins Definition Language

A JSON-LD language for describing models and interfaces for IoT Plug and Play devices and Azure Digital Twins entities. The language enables the IoT platform and IoT solutions to use the semantics of the entity.

Learn more

First and subsequent mentions: Spell out in full as Digital Twins Definition Language.

Abbreviation: DTDL

Applies to: Iot Hub, IoT Central, Digital Twins

Digital twin

A digital twin is a collection of digital data that represents a physical object. Changes in the physical object are reflected in the digital twin. In some scenarios, you can use the digital twin to manipulate the physical object. The Azure Digital Twins service uses models expressed in the Digital Twins Definition Language to represent digital twins of physical devices or higher-level abstract business concepts, enabling a wide range of cloud-based digital twin solutions. An IoT Plug and Play device has a digital twin, described by a Digital Twins Definition Language device model.

See also Device twin

Casing rules: Always lowercase.

Applies to: Iot Hub, IoT Central, Digital Twins, Device developer

Digital twin change events

When an IoT Plug and Play device is connected to an IoT hub, the hub can use its routing capability to send notifications of digital twin changes. The IoT Central data export feature can also forward digital twin change events to other services. For example, whenever a property value changes on a device, IoT Hub can send a notification to an endpoint such as an event hub.

Casing rules: Always lowercase.

Abbreviation: Always spell out in full to distinguish from other types of change event.

Applies to: Iot Hub, IoT Central

Digital twin graph

In the Azure Digital Twins service, you can connect digital twins with relationships to create knowledge graphs that digitally represent your entire physical environment. A single Azure Digital Twins instance can host many disconnected graphs, or one single interconnected graph.

Casing rules: Always lowercase.

First and subsequent mentions: Use digital twin graph on first mention, then use twin graph.

Applies to: Iot Hub

Direct method

A way to trigger a method to execute on a device by invoking an API on your IoT hub.

Casing rules: Always lowercase.

Applies to: Iot Hub

Downstream service

A relative term describing services that receive data from the current context. For example, in the context of Azure Digital Twins, Time Series Insights is a downstream service if you set up your data to flow from Azure Digital Twins into Time Series Insights.

Casing rules: Always lowercase.

Applies to: Iot Hub, IoT Central, Digital Twins

E

Endpoint

A named representation of a data routing service that can receive data from other services.

An IoT hub exposes multiple endpoints that enable your apps to connect to the IoT hub. There are device-facing endpoints that enable devices to perform operations such as sending device-to-cloud messages. There are service-facing management endpoints that enable back-end apps to perform operations such as device identity management. There are service-facing built-in endpoints for reading device-to-cloud messages. You can create custom endpoints to receive device-to-cloud messages dispatched by a routing rule.

Casing rules: Always lowercase.

Applies to: Iot Hub

Enrollment

In the Device Provisioning Service, an enrollment is the record of individual devices or groups of devices that may register with a linked IoT hub through autoprovisioning.

Casing rules: Always lowercase.

Applies to: Iot Hub, IoT Central, Device Provisioning Service

Enrollment group

In the Device Provisioning Service and IoT Central, an enrollment group identifies a group of devices that share an X.509 or symmetric key attestation mechanism.

Casing rules: Always lowercase.

Applies to: Iot Hub, Device Provisioning Service, IoT Central

Event Hubs-compatible endpoint

An IoT Hub endpoint that lets you use any Event Hubs-compatible method to read device messages sent to the hub. Event Hubs-compatible methods include the Event Hubs SDKs and Azure Stream Analytics.

Casing rules: Always lowercase.

Applies to: Iot Hub

Event handler

A process that's triggered by the arrival of an event. For example, you can create event handlers by adding event processing code to an Azure function, and sending data to it using endpoints and event routing.

Casing rules: Always lowercase.

Applies to: Iot Hub

Event routing

The process of sending events and their data from one device or service to the endpoint of another.

In Iot Hub, you can define routing rules to describe how messages should be sent. In Azure Digital Twins, event routes are entities that are created for this purpose. Azure Digital Twins event routes can contain filters to limit what types of events are sent to each endpoint.

Casing rules: Always lowercase.

Applies to: Iot Hub, Digital Twins

F

Field gateway

Enables connectivity for devices that can't connect directly to IoT Hub and is typically deployed locally with your devices.

Casing rules: Always lowercase.

Applies to: Iot Hub, IoT Central

G

Gateway

A gateway enables connectivity for devices that cannot connect directly to IoT Hub. See also field gateway, cloud gateway, and custom gateway.

Casing rules: Always lowercase.

Applies to: Iot Hub, IoT Central

Gateway device

An example of a field gateway. A gateway device can be standard IoT device or an IoT Edge device.

A gateway device enables connectivity for downstream devices that cannot connect directly to IoT Hub.

Casing rules: Always lowercase.

Applies to: Iot Hub, IoT Central, IoT Edge

H

Hardware security module

Used for secure, hardware-based storage of device secrets. It's the most secure form of secret storage for a device. A hardware security module can store both X.509 certificates and symmetric keys. In the Device Provisioning Service, an attestation mechanism can use a hardware security module.

Casing rules: Always lowercase.

First and subsequent mentions: Spell out in full on first mention as hardware security module.

Abbreviation: HSM

Applies to: Iot Hub, Device developer, Device Provisioning Service

I

ID scope

A unique value assigned to a Device Provisioning Service instance when it's created.

IoT Central applications make use of DPS instances and make the ID scope available through the IoT Central UI.

Casing rules: Always use ID scope.

Applies to: Iot Hub, IoT Central, Device Provisioning Service

Identity registry

A built-in component of an IoT hub that stores information about the individual devices permitted to connect to the hub.

Casing rules: Always lowercase.

Applies to: Iot Hub

Individual enrollment

Identifies a single device that the Device Provisioning Service can provision to an IoT hub.

Casing rules: Always lowercase.

Applies to: Iot Hub, Device Provisioning Service

Interface

In IoT Plug and Play, an interface describes related capabilities that are implemented by a IoT Plug and Play device or digital twin. You can reuse interfaces across different device models. When an interface is used in a device model, it defines a component of the device. A simple device only contains a default interface.

In Azure Digital Twins, interface may be used to refer to the top-level code item in a Digital Twins Definition Language model definition.

Casing rules: Always lowercase.

Applies to: Device developer, Digital Twins

IoT Edge

A service and related client libraries and runtime that enables cloud-driven deployment of Azure services and solution-specific code to on-premises devices. IoT Edge devices can aggregate data from other devices to perform computing and analytics before sending the data to the cloud.

Learn more

Casing rules: Always capitalize as IoT Edge.

First and subsequent mentions: Spell out as Azure IoT Edge.

Applies to: IoT Edge

IoT Edge agent

The part of the IoT Edge runtime responsible for deploying and monitoring modules.

Casing rules: Always capitalize as IoT Edge agent.

Applies to: IoT Edge

IoT Edge device

A device that uses containerized IoT Edge modules to run Azure services, third-party services, or your own code. On the device, the IoT Edge runtime manages the modules. You can remotely monitor and manage an IoT Edge device from the cloud.

Casing rules: Always capitalize as IoT Edge device.

Applies to: IoT Edge

IoT Edge hub

The part of the IoT Edge runtime responsible for module to module, upstream, and downstream communications.

Casing rules: Always capitalize as IoT Edge hub.

Applies to: IoT Edge

IoT Edge runtime

Includes everything that Microsoft distributes to be installed on an IoT Edge device. It includes Edge agent, Edge hub, and the IoT Edge security daemon.

Casing rules: Always capitalize as IoT Edge runtime.

Applies to: IoT Edge

IoT Hub

A fully managed Azure service that enables reliable and secure bidirectional communications between millions of devices and a solution back end. For more information, see What is Azure IoT Hub?. Using your Azure subscription, you can create IoT hubs to handle your IoT messaging workloads.

Learn more

Casing rules: When referring to the service, capitalize as IoT Hub. When referring to an instance, capitalize as IoT hub.

First and subsequent mentions: Spell out in full as Azure IoT Hub. Subsequent mentions can be IoT Hub. If the context is clear, use hub to refer to an instance.

Example usage: The Azure IoT Hub service enables secure, bidirectional communication. The device sends data to your IoT hub.

Applies to: Iot Hub

IoT Hub Resource REST API

An API you can use to manage the IoT hubs in your Azure subscription with operations such as creating, updating, and deleting hubs.

Casing rules: Always capitalize as IoT Hub Resource REST API.

Applies to: Iot Hub

IoT Hub metrics

A feature in the Azure portal that lets you monitor the state of your IoT hubs. IoT Hub metrics enable you to assess the overall health of an IoT hub and the devices connected to it.

Casing rules: Always capitalize as IoT Hub metrics.

Applies to: Iot Hub

IoT Hub query language

A SQL-like language for IoT Hub that lets you query your jobs, digital twins, and device twins.

Casing rules: Always capitalize as IoT Hub query language.

First and subsequent mentions: Spell out in full as IoT Hub query language, if the context is clear subsequent mentions can be query language.

Applies to: Iot Hub

IoT Plug and Play bridge

An open-source application that enables existing sensors and peripherals attached to Windows or Linux gateways to connect as IoT Plug and Play devices.

Casing rules: Always capitalize as IoT Plug and Play bridge.

First and subsequent mentions: Spell out in full as IoT Plug and Play bridge. If the context is clear, subsequent mentions can be bridge.

Applies to: Iot Hub, Device developer, IoT Central

IoT Plug and Play conventions

A set of conventions that IoT devices should follow when they exchange data with a solution.

Casing rules: Always capitalize as IoT Plug and Play conventions.

Applies to: Iot Hub, IoT Central, Device developer

IoT Plug and Play device

Typically a small-scale, standalone computing device that collects data or controls other devices, and that runs software or firmware that implements a device model. For example, an IoT Plug and Play device might be an environmental monitoring device, or a controller for a smart-agriculture irrigation system. An IoT Plug and Play device might be implemented directly or as an IoT Edge module.

Casing rules: Always capitalize as IoT Plug and Play device.

Applies to: Iot Hub, IoT Central, Device developer

IoT extension for Azure CLI

An extension for the Azure CLI. The extension lets you complete tasks such as managing your devices in the identity registry, sending and receiving device messages, and monitoring your IoT hub operations.

Learn more

Casing rules: Always capitalize as IoT extension for Azure CLI.

Applies to: Iot Hub, IoT Central, IoT Edge, Device Provisioning Service, Device developer

J

Job

In the context of IoT Hub, jobs let you schedule and track activities on a set of devices registered with your IoT hub. Activities include updating device twin desired properties, updating device twin tags, and invoking direct methods. IoT Hub also uses jobs to import to and export from the identity registry.

In the context of IoT Central, jobs let you manage your connected devices in bulk by setting properties and calling commands. IoT Central jobs also let you update cloud properties in bulk.

Casing rules: Always lowercase.

Applies to: Iot Hub, IoT Central

L

Leaf device

A device with no downstream devices connected. Typically leaf devices are connected to a gateway device.

Casing rules: Always lowercase.

Applies to: IoT Edge, IoT Central, Device developer

Lifecycle event

In Azure Digital Twins, this type of event is fired when a data item—such as a digital twin, a relationship, or an event handler is created or deleted from your Azure Digital Twins instance.

Casing rules: Always lowercase.

Applies to: Digital Twins, Iot Hub, IoT Central

Linked IoT hub

An IoT hub that is linked to a Device Provisioning Service instance. A DPS instance can register a device ID and set the initial configuration in the device twins in linked IoT hubs.

Casing rules: Always capitalize as linked IoT hub.

Applies to: Iot Hub, Device Provisioning Service

M

MQTT

One of the messaging protocols that IoT Hub and IoT Central support for communicating with devices. MQTT doesn't stand for anything.

Learn more

First and subsequent mentions: MQTT

Abbreviation: MQTT

Applies to: Iot Hub, IoT Central, Device developer

Model

A definition of a type of entity in your physical environment, including its properties, telemetries, and components. Models are used to create digital twins that represent specific physical objects of this type. Models are written in the Digital Twins Definition Language.

In the Azure Digital Twins service, models define devices or higher-level abstract business concepts. In IoT Plug and Play, device models describe devices specifically.

Casing rules: Always lowercase.

Applies to: Iot Hub, IoT Central, Digital Twins, Device developer

Model ID

When an IoT Plug and Play device connects to an IoT Hub or IoT Central application, it sends the model ID of the Digital Twins Definition Language model it implements. Every model as a unique model ID. This model ID enables the solution to find the device model.

Casing rules: Always capitalize as model ID.

Applies to: Iot Hub, IoT Central, Device developer, Digital Twins

Model repository

Stores Digital Twins Definition Language models and interfaces. A solution uses a model ID to retrieve a model from a repository.

Casing rules: Always lowercase.

Applies to: Iot Hub, IoT Central, Digital Twins

Model repository REST API

An API for managing and interacting with a model repository. For example, you can use the API to add and search for device models.

Casing rules: Always capitalize as model repository REST API.

Applies to: Iot Hub, IoT Central, Digital Twins

Module

The IoT Hub device SDKs let you instantiate modules where each one opens an independent connection to your IoT hub. This lets you use separate namespaces for different components on your device.

Module identity and module twin provide the same capabilities as device identity and device twin but at a finer granularity.

In IoT Edge, a module is a Docker container that you can deploy to IoT Edge devices. It performs a specific task, such as ingesting a message from a device, transforming a message, or sending a message to an IoT hub. It communicates with other modules and sends data to the IoT Edge runtime.

Casing rules: Always lowercase.

Applies to: Iot Hub, IoT Edge, Device developer

Module identity

A unique identifier assigned to every module that belongs to a device. Module identities are also registered in the identity registry.

The module identity details the security credentials the module uses to authenticate with the IoT Hub or, in the case of an IoT Edge module to the IoT Edge hub.

Casing rules: Always lowercase.

Applies to: Iot Hub, IoT Edge, Device developer

Module image

The docker image the IoT Edge runtime uses to instantiate module instances.

Casing rules: Always lowercase.

Applies to: IoT Edge

Module twin

Similar to device twin, a module twin is JSON document that stores module state information such as metadata, configurations, and conditions. IoT Hub persists a module twin for each module identity that you provision under a device identity in your IoT hub. Module twins enable you to synchronize module conditions and configurations between the module and the solution back end. You can query module twins to locate specific modules and query the status of long-running operations.

Casing rules: Always lowercase.

Applies to: Iot Hub

O

Ontology

In the context of Digital Twins, a set of models for a particular domain, such as real estate, smart cities, IoT systems, energy grids, and more. Ontologies are often used as schemas for knowledge graphs like the ones in Azure Digital Twins, because they provide a starting point based on industry standards and best practices.

Learn more

Applies to: Digital Twins

Operations monitoring

A feature of IoT Hub that lets you monitor the status of operations on your IoT hub in real time. IoT Hub tracks events across several categories of operations. You can opt into sending events from one or more categories to an IoT Hub endpoint for processing. You can monitor the data for errors or set up more complex processing based on data patterns.

Casing rules: Always lowercase.

Applies to: Iot Hub

P

Physical device

A real IoT device that connects to an IoT hub. For convenience, many tutorials and quickstarts run IoT device code on a desktop machine rather than a physical device.

Casing rules: Always lowercase.

Applies to: Iot Hub, IoT Central, Device developer, IoT Edge

Primary and secondary keys

When you connect to a device-facing or service-facing endpoint on an IoT hub or IoT Central application, your connection string includes key to grant you access. When you add a device to the identity registry or add a shared access policy to your hub, the service generates a primary and secondary key. Having two keys enables you to roll over from one key to another when you update a key without losing access to the IoT hub or IoT Central application.

Casing rules: Always lowercase.

Applies to: Iot Hub, IoT Central

Properties

In the context of a digital twin, data fields defined in an interface that represent some persistent state of the digital twin. You can declare properties as read-only or writable. Read-only properties, such as serial number, are set by code running on the IoT Plug and Play device itself. Writable properties, such as an alarm threshold, are typically set from the cloud-based IoT solution.

Casing rules: Always lowercase.

Applies to: Iot Hub, IoT Central, Digital Twins, Device developer

Property change event

An event that results from a property change in a digital twin.

Casing rules: Always lowercase.

Applies to: Iot Hub, IoT Central, Digital Twins

Protocol gateway

A gateway typically deployed in the cloud to provide protocol translation services for devices connecting to an IoT hub or IoT Central application.

Casing rules: Always lowercase.

Applies to: Iot Hub, IoT Central

R

Registration

A record of a device in the IoT Hub identity registry. You can register or device directly, or use the Device Provisioning Service to automate device registration.

Casing rules: Always lowercase.

Applies to: Iot Hub, IoT Central, Device Provisioning Service

Registration ID

A unique device identity in the Device Provisioning Service. The registration ID may be the same value as the device identity.

Casing rules: Always lowercase.

Applies to: Iot Hub, IoT Central, Device Provisioning Service

Relationship

Used in the Azure Digital Twins service to connect digital twins into knowledge graphs that digitally represent your entire physical environment. The types of relationships that your twins can have are defined in the Digital Twins Definition Language model.

Casing rules: Always lowercase.

Applies to: Digital Twins

Reported configuration

In the context of a device twin, this refers to the complete set of properties and metadata in the device twin that are reported to the solution back end.

Casing rules: Always lowercase.

Applies to: Iot Hub, Device developer

Reported properties

In the context of a device twin, reported properties is a subsection of the device twin. Reported properties can only be set by the device but can be read and queried by a back-end app.

Casing rules: Always lowercase.

Applies to: Iot Hub, Device developer

Retry policy

A way to handle transient errors when you connect to a cloud service.

Casing rules: Always lowercase.

Applies to: Iot Hub, IoT Central, Device developer

Routing rule

A feature of IoT Hub used to route device-to-cloud messages to a built-in endpoint or to custom endpoints for processing by your solution back end.

Casing rules: Always lowercase.

Applies to: Iot Hub

S

SASL/PLAIN

A protocol that Advanced Message Queueing Protocol uses to transfer security tokens.

Learn more

Abbreviation: SASL/PLAIN

Applies to: Iot Hub

Service REST API

A REST API you can use from the solution back end to manage your devices. For example, you can use the Iot Hub service API to retrieve and update device twin properties, invoke direct methods, and schedule jobs. Typically, you should use one of the higher-level service SDKs.

Casing rules: Always service REST API.

Applies to: Iot Hub, IoT Central, Device Provisioning Service, IoT Edge

Service operations endpoint

An endpoint that an administrator uses to manage service settings. For example, in the Device Provisioning Service you use the service endpoint to manage enrollments.

Casing rules: Always lowercase.

Applies to: Iot Hub, Device Provisioning Service, IoT Edge, Digital Twins

Shared access policy

A way to define the permissions granted to anyone who has a valid primary or secondary key associated with that policy. You can manage the shared access policies and keys for your hub in the portal.

Casing rules: Always lowercase.

Applies to: Iot Hub, IoT Edge, Device Provisioning Service

Shared access signature

A shared access signature is a signed URI that points to one or more resources such as an IoT hub endpoint. The URI includes a token that indicates how the resources can be accessed by the client. One of the query parameters, the signature, is constructed from the SAS parameters and signed with the key that was used to create the SAS. This signature is used by Azure Storage to authorize access to the storage resource.

Casing rules: Always lowercase.

Abbreviation: SAS

Applies to: Iot Hub, Digital Twins, IoT Central, IoT Edge

Simulated device

For convenience, many of the tutorials and quickstarts run device code with simulated sensors on your local development machine. In contrast, a physical device such as an MXCHIP has real sensors and connects to an IoT hub.

Casing rules: Always lowercase.

Applies to: Iot Hub, IoT Central, Device developer, IoT Edge, Digital Twins, Device Provisioning Service

Solution

In the context of IoT, solution typically refers to an IoT solution that includes elements such as devices, device apps, an IoT hub, other Azure services, and back-end apps.

Casing rules: Always lowercase.

Applies to: Iot Hub, IoT Central, Device Provisioning Service, IoT Edge, Digital Twins

System properties

In the context of a device twin, the read-only properties that include information regarding the device usage such as last activity time and connection state.

Casing rules: Always lowercase.

Applies to: Iot Hub

T

Tag

In the context of a device twin, tags are device metadata stored and retrieved by the solution back end in the form of a JSON document. Tags are not visible to apps on a device.

Casing rules: Always lowercase.

Applies to: Iot Hub

Target condition

In an IoT Edge deployment, the target condition selects the target devices of the deployment. The target condition is continuously evaluated to include any new devices that meet the requirements or remove devices that no longer do.

Casing rules: Always lowercase.

Applies to: IoT Edge

Telemetry

The data, such as wind speed or temperature, sent to an IoT hub that was collected by a device from its sensors.

Unlike properties, telemetry is not stored on a digital twin; it is a stream of time-bound data events that need to be handled as they occur.

In IoT Plug and Play and Azure Digital Twins, telemetry fields defined in an interface represent measurements. These measurements are typically values such as sensor readings that are sent by devices, like IoT Plug and Play devices, as a stream of data.

Casing rules: Always lowercase.

Example usage: Don't use the word telemetries, telemetry refers to the collection of data a device sends. For example: When the device connects to your IoT hub, it starts sending telemetry. One of the telemetry values the device sends is the environmental temperature.

Applies to: Iot Hub, IoT Central, Digital Twins, IoT Edge, Device developer

Telemetry event

An event in an IoT hub that indicates the arrival of telemetry data.

Casing rules: Always lowercase.

Applies to: Iot Hub

Twin queries

A feature of IoT Hub that lets you use a SQL-like query language to retrieve information from your device twins or module twins.

Casing rules: Always lowercase.

Applies to: Iot Hub

Twin synchronization

The process in IoT Hub that uses the desired properties in your device twins or module twins to configure your devices or modules and retrieve reported properties from them to store in the twin.

Casing rules: Always lowercase.

Applies to: Iot Hub

U

Upstream service

A relative term describing services that feed data into the current context. For instance, in the context of Azure Digital Twins, IoT Hub is considered an upstream service because data flows from IoT Hub into Azure Digital Twins.

Casing rules: Always lowercase.

Applies to: Iot Hub, IoT Central, Digital Twins