# The Integration of Azure Sphere and Azure Cloud Services for Internet of Things
## 1 Introduction  
With the rapid evolution of the Internet of Things (IoT), more and more network-enabled devices are involved to pave the way for connected vehicles [1], industrial IoT [2; 3], connected healthcare [4; 5], smart cities [6] and smart home [7] from an infrastructure perspective. Meanwhile, the considerations have been shifted gradually from the real-time data stream to the valuable intelligence derived from the data. Hence, more and more public cloud computing providers, such as Amazon, Microsoft, Google and IBM, are involved in IoT era to provide a variety of services including data aggregation, data filtering, data storage, data processing and data visualization for IoT support [8].  
However, there are still some issues and challenges that cannot be neglected in face of ever-growing end devices in large-scale IoT systems. Firstly, the need to incorporate the high-value security into every low-cost (much cheaper than 10 US dollars) network-connected IoT devices is currently underestimated because of the limited development costs and device capabilities [9; 10]. Consequently, these network-connected devices are extremely vulnerable to aggressive assault from network attackers [11]. Obviously, this challenge is not considered by public cloud computing providers since their concentration are mainly put on the software and services to make it simple for developing, deploying and maintaining IoT applications. Secondly, according to the literature [12; 13; 14; 15; 16; 17], few existingsolutions considered the security aspects all the way from the device to the cloud. To some extent, most of them have achieved the security and privacy goals in one specific layer or multiple layers, rather than overall system security. Thirdly, as hundreds of thousands of end devices are involved in the IoT system, the device provision, configuration as well as management can hardly be integrated in a secure and efficient way. Hence, a more feasible integrated solution is urgently needed to ensure high-value security from the device layer to the cloud layer.  
Based on the current IoT trend, we propose an integrated solution that includes Azure Sphere devices and Azure cloud services to address the challenges of overall security, cost and device management. By taking advantage of the Azure Sphere and Azure cloud services, this integration is capable of maintaining the low-cost requirement. Moreover, a proof of concept application (a remote monitoring and feedback control system), namely its design and implement to validate the proposed integrated solution, is detailed. More specifically, the contributions of this study are the following.  
* A new IoT integrated solution including hardware, software and services is proposed based on Azure Sphere device and Azure cloud services to meet the requirements of high security and low cost.
* The hardware prototypes for Azure Sphere device, which act either as a direct connected device or a gateway, are designed and implemented based on the MT3620 development kit.
* The programs for MT3620 and CC2530 ZigBee devices, as well as applications for Windows devices are designed and implemented. Meanwhile, a proof of concept for the proposed integration is demonstrated and verified based on the hardware prototypes and Azure cloud services.  
The remainder of this article is structured as follows. The state-of-art of IoT integrated solutions are reviewed in Section 2. The overall design of the proposed integration is provided in Section 3. The implementation details that comprise hardware components, software design and Azure cloud integration are presented in Section 4. In Section 5, the experimental results are shown concerning the device layer, cloud layer and application layer. The discussion of the comparison between the proposed security integration and the existing security solutions is given in Section 6. Finally, the conclusion is summarized in Section 7.