The Internet of things (IoT) is emerging as the next big wave of digital presence for billions of devices on the Internet. Smart cities are a practical manifestation of IoT, with the goal of efficient, reliable, and safe delivery of city utilities like water, power, and transport to residents, through their intelligent management. A data-driven IoT software platform is essential for realizing manageable and sustainable smart utilities and for novel applications to be developed upon them. Here, we propose such service-oriented software architecture to address 2 key operational activities in a smart utility: the IoT fabric for resource management and the data and application platform for decision-making. Our design uses Open Web standards and evolving network protocols, cloud and edge resources, and streaming big data platforms. We motivate our design requirements using the smart water management domain; some of these requirements are unique to developing nations. We also validate the architecture within a campus-scale IoT testbed at the Indian Institute of Science, Bangalore and present our experiences. Our architecture is scalable to a township or city while also generalizable to other smart utility domains. Our experiences serve as a template for other similar efforts, particularly in emerging markets and highlight the gaps and opportunities for a data-driven IoT software architecture for smart cities.As the number of IoT devices soon reaches the billions, it is essential to have a distributed software architecture that facilitates the sustainable management of these physical devices and communication networks and access to their data streams and controls for developing innovative IoT applications. Three synergistic concepts come together to enable this. Service-oriented architecture (SOA) 7,8 offers standard mechanisms and protocols for discovery, addressing, access control, invocation, and composition of services that are available on the World Wide Web (WWW), by leveraging and extending Web-based protocols such as the Hypertext Transfer Protocol (HTTP) and open representation models like the Extensible Markup Language (XML). 9 Cloud computing is a manifestation of this paradigm where infrastructure, platform, and software resources are available "as a service" (IaaS, PaaS, and SaaS), often served from geographically distributed data centers worldwide. These offer economies of scale and enable access to elastic resources using a pay-as-you-go model. 10 Such commodity clusters on the cloud have also enabled the growth of big data platforms that allow data-driven applications to be composed and scaled on tens or hundreds of virtual machines (VMs) and deal with both data volume and velocity, among other dimensions. 11 Unlike traditional enterprise or scientific applications, however, the IoT domain is distinct in the way these technologies converge to support emerging applications. (1) IoT integrates hardware, communication, software, and analytics and links the physical and the digital world. Hence, infrastructu...
