RPL over Internet of Things: Challenges, Solutions, and Recommendations

Internet of Things (IoT) has recently attracted significant research interest. Routing protocols have a vital task in meeting the needs of IoT devices with the necessary ability to interwork seamlessly. The major target of this work is to help the IoT research community in understanding all aspects of the most popular IoT routing protocol, which refers to the IPv6 routing protocol for Low-Power and Lossy Networks (RPL). In this work, after investigating the major challenges of RPL and studying a body of the proposed RPL solutions, which are fragmented based on these challenges, we get ultimately capable of shedding the light on all challenges encountered by IoT researchers along with their role in enhancing the RPL and providing what is expected to be dealt with them in a professional manner bearing in mind the limitations of IoT nodes. Not only that, but the research history of RPL is professionally analyzed based on RPL challenges over the years 2010 and 2020 using Google Scholar, Scopus, and IEEE Xplore. Interestingly, the conclusions and recommendations of this study are presented along with effective directions of the future of RPL, to be followed, and its applicability. As a result, the authors anticipate that this study will be useful to all RPL researchers and designers.