Scalable Web Technology for the Internet of Things

The Internet of Things (IoT) can be considered as a modern manifestation of Mark Weiser’s classic vision of ubiquitous computing where tiny networked computers become part of everyday objects interweaving the virtual world and the physical world. The concept of the IoT originated some 15 years ago from linking real-world artifacts to virtual counterparts through radio-frequency identification (RFID) tags. More recently, environments have become ‘smart’ by augmenting physical objects with sensing or actuation capabilities and networking them with digital services. The ongoing standardization of Internet protocols for such IoT devices enables the seamless integration of smart things into the Internet. This trend is expected to eventually result in hundreds of billions of connected devices that need to be programmed, managed, and maintained. It has been shown that Web technology can significantly ease this process by providing well-known patterns and tools for developers and users. The existing solutions are, however, often too heavyweight for highly resource-constrained IoT devices. Indeed, most connected devices are expected to remain resource-constrained, as progress in technology witnessed by Moore’s Law is primarily leveraged to minimize dimensions, power consumption, and unit costs. This dissertation presents a comprehensive solution for the seamless integration of highly resource-constrained IoT systems into the World Wide Web. Our thesis is that existing protocols and programming models do not effectually meet the needs of the IoT. We identify two key challenges for the vision to succeed: application-layer interoperability and improved usability for both developers and users. Both requirements can be met by an approach that amalgamates results from the field of Wireless Sensor Networks and the World Wide Web. This leads to the research questions (i) how to scale Web technology down to resource-constrained devices, (ii) how to scale it up to hundreds of billions of devices, and (iii) how to use it to improve the usability of the tiny networked computers. Our work addresses the resulting challenges with the following contributions: Being actively involved in the design and standardization of the Constrained Application Protocol (CoAP) within the Internet Engineering Task Force (IETF), we (i) evaluate the new Web protocol