Why Should You Use Azure IoT Suite Over Event Hub?
With the introduction of Azure IoT Suite and IoT Hub, Microsoft is making a serious play for the millions of devices and billions of messages that are already out there, or will be as the Internet of Things takes off. The future of IoT is very bright, but it is also extremely disorganized — security and proper design of device architecture is a major concern and liability, as can be seen in numerous recent hacks. The creation of IoT Hub is a strong play to better facilitate the communication methods with, security of, and administration for a large-scale IoT network.
IoT Suite is, at its core, a package of functionality built on top of the IoT Hub, which is similar to the Azure Event Hub platform that already exists. Azure Event Hub is a proven method of pushing large amounts of data from many devices, but on its own it provides only ingress/egress messaging, and none of the functionality that is required to maintain a secure, diverse network of IoT devices. IoT Suite assists by providing some of the following features:
- Device registration
- Protocol adaptation
- Device administration
Additionally, since IoT Hub behaves similarly to Event Hub, you have the same access to hot-path and cold-path event processing, such as to Azure Stream Analytics.
Now I’ll quickly break down some of the features and components of IOT Hub:
The Azure IoT Hub supports both HTTP and AMQP out of the box. With these two technologies, any IP-capable field devices are able to communicate with the hub (if they don’t, a field gateway can also be used to facilitate communication). For many devices, however, HTTP/AMQP are not sufficient; Azure therefore provides the ability to provision and utilize specialized Cloud Protocol Gateways by deploying a specialized Cloud Service worker role.
As part of Microsoft’s newfound love of open source, they work with the Apache Proton team (Apache Qpid), among other technologies, to ensure that devices with stringent memory requirements running on C or other languages can use the Proton library to communicate with IoT Hub.
Device Provisioning and Management
Azure IoT suite also allows for powerful administration of devices. Maintaining device metadata is crucial, and Azure supports storing JSON metadata for each device, and updating it at will. IoT Suite is flexible enough to support devices using many different device service models, and allows for easy device provisioning and familiar definitions of access control policies. C2D and D2C (cloud-to-device and device-to-cloud) endpoints are provided to allow solutions to communicate with devices, and endpoints for the IoT Suite itself are exposed to perform administration tasks and device provisioning.
The vast array of functionality that Azure provides also aids in the complete administration of IoT devices: firmware updates can be downloaded by devices from a storage account or Azure CDN; access control can be administered through Azure Active Directory; error reporting and analysis can be done with the hot- and cold-path routes made available with technologies like Azure Stream Analytics and Azure HDInsight; and Azure provides SDK’s and quickstart template code for quickly prototyping and implementing various device administration tasks.
Device Identity Management and Security
Azure IoT hub maintains a device registry containing information about each device, including a deviceId, generationId, status, and other metadata. When a message is sent from a device to the cloud, the message is stamped with some of these properties to prevent spoofing. Refer to the developer guide for more information.
Secure transmission with HTTP and AMQP is supported, with a token in the auth header for HTTP messages, and SASL Plain or Claims-Based Security for AMQP.
It is important to keep in mind that IoT hub is built for massive scalability: while Event Hub is more constrained in terms of simultaneous device connectivity — each event hub can support only 5,000 simultaneous AMQP connections, for example — each IoT hub can scale up to a maximum of 2,000 “units”, for a total of one million simultaneous devices per hub. On top of that, there can be up to 10 IoT hubs per subscription. The potential is certainly there for Azure and IoT Hub to handle tremendous numbers of devices.
Because of the different natures of the two platforms, pricing is naturally different. Event Hub is priced on ingress/egress, and is noticeably cheaper than IoT Hub, which is $25 for a single low-frequency IoT Hub unit (the number of hub units is specified when provisioning an IoT Hub, with the cost scaling up with per unit). The added cost of IoT Hub comes both from the large amount of additional functionality provided, the handling of D2C and C2D messaging, and from drastically increased scalability.
It is difficult to make an apples-to-apples comparison between IoT Suite/Hub and Azure Event Hub; in a sense, IoT Suite contains the majority of the functionality of Event Hub (except as regards device partitions as used in Event Hub), but it provides a large suite of complementary features, and orders of magnitude more simultaneous connections available.
Using IoT Suite is certainly not for everyone — in some cases, administration of IoT devices may be implemented by the device vendor already in different ways, or significant portions of IoT suite are simply not needed for a solution. But in the cases where a complete, robust, and scalable solution for provisioning, communicating with, updating, and administering large numbers of disparate devices is required — I know there are many, and there will be many more as the Internet of Things continues to take off — it would be tough to find a better complete end-to-end solution than Azure and IoT Hub.