Towards better scalability for IoT-cloud interactions via combined exploitation of MQTT and CoAP

It is manifest the growing research and industrial interest in scalable solutions for the efficient integration of large amounts of deployed sensors and actuators (Internet of Things - IoT-devices) and cloud-hosted virtualized resources for elastic storage and processing (including big data online stream processing). Such relevant attention is also demonstrated by the emergence of interesting IoT-cloud platforms from industry and open-source communities, as well as by the flourishing research area of fog/edge computing, where decentralized virtual resources at edge nodes can support enhanced scalability and reduced latency via locality-based optimizations. In this perspective, this paper proposes an innovative distributed architecture combining machine-to-machine industry-mature protocols (i.e., MQTT and CoAP) in an original way to enhance the scalability of gateways for the efficient IoT-cloud integration. In addition, the paper presents how we have applied the approach in the practical experience of efficiently and effectively extending the implementation of the open-source gateway that is available in the industry-oriented Kura framework for IoT.