ARPL: Supporting Adaptive Mixing of RPL Modes to Overcome Memory Overflow

IPv6 Routing Protocol for Low Power and Lossy Networks (RPL) proposed by Internet Engineering Task Force (IETF) has been adopted to suit Internet of Things (IoT) requirements. However, both the storing and non-storing modes of operation for RPL brings about certain limitations. In case of storing mode of RPL, if an intermediate node along the routing path overflows, new nodes become unreachable whereas, for the non-storing mode of RPL, the entire routing topology is only saved at the root node resulting in increased congestion near the root. Therefore, in this paper, we propose a low overhead Adaptive RPL (ARPL) algorithm which allows flexibility between storing and non-storing modes of operation. Here, the benefits of both the operating modes of RPL are utilized to avoid additional control message exchange, thereby making network resource-aware. We also observe that ARPL performs better than one state-of-the-art competitor in terms of storage and memory overflow by allowing the said flexibility of switching modes. Finally, we simulate ARPL using Cooja in Contiki operating system to evaluate the performance of ARPL. The simulation results show that ARPL achieves higher packet delivery ratio (PDR) in downward communication (e.g. query mode) while keeping convergence time same. It also shows that even in the mixed mode more than 90% nodes are operating in storing mode which improves Point to Point (P2P) communication with reduced traffic near the root thus allowing nodes to save energy.