MSE-RPL: Mobility Support Enhancement in RPL for IoT Mobile Applications

Due to the expansion of IoT applications which causes the generation of a massive amount of data, data routing is one of the most important challenges in these networks. The Routing Protocol for Low-power and Lossy Networks (RPL) was developed to cope with the Low-power and lossy network constraints, which play a significant role in IoT networks. Although most IoT applications involve mobility and topology change that makes mobility support a substantial need to prevent disconnection of nodes and data loss, the RPL is designed for static networks. This article proposes a mobility support method called MSE as an extension of RPL. The MSE supports mobility of all nodes except the root node, and it provides a seamless connection during the mobility. It also manages a situation when a physical obstacle settles between two paired nodes in a dynamic environment. To this end, it uses a dynamic trickle timer with two different ranges, a neighbor link quality table, a function to select the best parent in case of mobility, confidence, critical zones, and a blacklist. Simulations in multiple scenarios indicate that MSE, despite causing a slight increase in signaling cost and power consumption, significantly reduces hand-off delay, increases Packet Delivery Ratio, reduces the number of lost data packets, and outperforms both RPL as a reactive and mRPL as a proactive protocol regarding mobility.