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Posted 25 Aug 2018
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Azure IoT Hub Overview

, 25 Aug 2018
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Azure IoT hub allows you to get on with developing cool IoT stuff, and not worry about how it all gets connected up and managed.

Introduction

I really enjoy working on IoT projects, and have spent a lot of time tinkering with electronics and robotics. When you want to go into production with your IoT devices however, you not only have device itself to worry about, you also need to be able to connect it up to the Internet (most likely), monitor the data coming from it, and manage the device out in the wild..... and this is the reason for the existence of IoT hub! ... Azure IoT hub allows you to get on with developing cool IoT stuff, and not worry about how it all gets connected up and managed.

Summary

The Internet of Things (IoT) offers businesses immediate and real-world opportunities to reduce costs, increase revenue, as well as transform their businesses. Azure IoT hub is a managed IoT service which is hosted in the cloud. It allows bi-directional communication between IoT applications and the devices it manages. This cloud-to-device connectivity means that you can receive data from your devices, but you can also send commands and policies back to the devices. How Azure IoT hub differs from existing solutions is that it also provides the infrastructure to authenticate, connect and manage the devices connected to it.

The Detail

Azure IoT Hub allows full-featured, scaleable IoT solutions. Virtually any device can be connected to Azure IoT Hub and it can scale up to millions of devices. Events can be tracked and monitored, such as the creation, failure and connection of devices.

Azure IoT Hub provides:

  • Device libraries for the most commonly used platforms and languages for easy device connectivity.
  • Secure communications with multiple options for device-to-cloud and cloud-to-device hyper-scale communication.
  • Queryable storage of per-device state information as well as meta-data.

Managing Devices with IoT Hub

The needs and requirements of IoT operators vary substantially in different industries, from transport to manufacturing to agriculture to utilities. There is also a wide variation in the types of devices used by IoT operators. IoT Hub is able to provide the capabilities, patterns and code libraries to allow developers to build management solutions that can manage very diverse sets of devices.

Configuring and Controlling Devices

Devices which are connected to IoT Hub can be managed using an array of built-in functionality. This means that-

  • Device metadata and state information for all your devices can be stored, synchronized and queried.
  • Device state can be set either per-device, or in groups depending on common characteristics of the devices.
  • A state change in a device can be automatically responded to by using message routing integration.

Lifecycle of Devices with IoT Hub

Plan: Operators can create a device metadata scheme that allows them to easily carry out bulk management operations.

Provision: New devices can be securely provisioned to IoT Hub and operators can quickly discover device capabilities. The IoT Hub identity registry is used to create device identities and credentials.

Configure: Device management operations, such as configuration changes and firmware updates can be done in bulk or by direct methods, while still maintaining system security.

Monitor: Operators can be easily alerted to any issues arising and at the same time, the device collection health can be monitored, as well as the status of any ongoing operations.

Retire: Devices need to be replaced, retired or decommissioned. The IoT Hub identity registry is used to withdraw device identities and credentials.

Device Management Patterns

IoT Hub supports a range of device management patterns including:

  • Reboot
  • Factory reset
  • Configuration
  • Firmware update
  • Reporting progress and status

These patterns can be extended to fit your exact situation. Alternatively, new patterns can be designed based on these templates.

Connecting Your Devices

You can build applications which run on your devices and interact with IoT Hub using the Azure IoT device SDK. Windows, Linux distributions and real-time operating systems are supported platforms. Supported languages currently include:

  • C
  • C#
  • Java
  • Python
  • Node.js

Messaging Patterns

Azure IoT Hub supports a range of messaging patterns including:

  • Device to cloud telemetry
  • File upload from devices
  • Request-reply methods which enables devices to be controlled from the cloud

Message Routing and Event Grid

Both IoT Hub message routing and IoT Hub integration with Event Grid make it possible to stream data from your connected devices. However, there are differences. Message routing allows users to route device-to-cloud messages to a range of supported service endpoints such as Event Hubs and Azure Storage containers while IoT Hub integration with Event Grid is a fully managed routing service which can be extended into 3rd party business applications.

Device Data Can Be Routed

In Azure IoT Hub message routing functionality is built in. This allows you to set up automatic rules-based message fan-out. You can use message routing to decide where your hub sends your devices’ telemetry. Routing messages to multiple endpoints doesn’t incur any extra costs.

Building End-to-end Solutions

End-to-end solutions can be built by integrating IoT Hub with other Azure services. For example:

  • Business processes can be automated using Azure Logic Apps.
  • You can run analytic computations in real-time on the data from your devices using Azure Stream Analytics.
  • AI models and machine learning can be added using Azure Machine Learning.
  • You can respond rapidly to critical events with Azure Event Grid.

Azure IoT Hub or Azure Event Hub?

Both Azure IoT Hub and Azure Event Hub are cloud services which can ingest, process and store large amounts of data. However, they were designed with different purposes in mind. Event Hub was developed for big data streaming while IoT Hub was designed specifically to connect IoT devices at scale to the Azure Cloud. Therefore, which one you choose to use will depend on the demands of your business.

IoT Hub allows data to be sent on secure communications channels. Each device connects securely to the hub and each device can be managed securely. You can control access at the per-device level and devices are automatically provisioned to the correct hub when the device first boots up.

There’s also a range of different types of authentication depending on device capabilities, including SAS SAS token-based authentication, individual X.509 certificate authentication for secure, standards-based authentication, as well as X.509 CA authentication.

High Availability and Disaster Recovery

Uptime goals vary from business to business. Azure IoT Hub offers three main High Availability (HA) and Disaster Recovery (DR) features including:

Intra-region HA: The IoT Hub service provides intra-region HA by implementing redundancies in almost all layers of the service. The SLA published by the IoT Hub service is achieved by making use of these redundancies and are available automatically to developers. However, transient failures should be expected when using cloud computing; therefore, appropriate retry policies need to be built into components which interact with the cloud in order to deal with these transient failures.

Cross region DR: Situations may arise when a datacentre suffers from extended outages or some other physical failure. It is rare, but possible that intra region HA capability may not be able to help in some of these situations. However, IoT Hub has a number of possible solutions for recovering from extended outages or physical failures. In these situations, a customer can have a Microsoft initiated failover or a manual failover.

Both of these options offer the following recovery time objectives (RTO):

Achieving Cross Region HA

If the RTOs provided by either the Microsoft initiated failover or manual failover aren’t sufficient for your uptime goals, then another option is to implement a per-device automatic cross region failover mechanism. In this model, the IoT solution runs in a primary and secondary datacentre in two different locations. If there’s an outage or a loss of network connectivity in the primary region, then devices can use the secondary location.

Choosing the Right IoT Hub Tier

Azure IoT hub offers two tiers, basic and standard. The basic tier which is uni-directional from devices to the cloud, is more suitable if the data is going to be gathered from devices and analysed centrally. However, if you want bi-directional communication, enabling you to, for example, control devices remotely, then the standard tier is more appropriate. Both tiers have the same security and authentication features.

Each tier has three different sizes (1, 2 and 3), depending on how much data they can handle in a day. For instance, a level 3 unit can handle 300 million messages a day while a level 1 unit can handle 400,000.

If you are playing with IoT, or about to bring a device into the world, it's worth your while checking out Azure IoT Hub!

History

  • 25th August, 2018: Version 1

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

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About the Author

AJSON
Engineer
United Kingdom United Kingdom
Allen is a consulting architect with a background in enterprise systems. His current obsessions are IoT, Big Data and Machine Learning. When not chained to his desk he can be found fixing broken things, playing music very badly or trying to shape things out of wood. He runs his own company specializing in systems architecture and scaling for big data and is involved in a number of technology startups.

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