Mobility support enhancement for RPL with multiple sinks

In recent years, low power and lossy networks (LLNs) have attracted the attention of researchers. They typically operate with strict resource constraints in communication, computation, memory, and energy. Routing protocol for LLNs (RPL) is an ad-hoc distance vector routing protocol for LLNs that adapts IPv6 and runs on top of IEEE 802.15.4 standard. Although RPL was originally designed for static topologies, for many applications mobility support has been a major requirement in LLNs. In addition, part of these applications requires multiple sink nodes rather than one sink node. This is due to the fact that in a data collection wireless sensor network (WSN), only one sink easily leads to a faster energy depletion, more packet loss, higher latency, and smaller network range. Deploying multiple sinks in the network can help solve these problems. This paper focuses on addressing mobility support in RPL with multiple sinks. We propose an enhancement based on signal strength monitoring and rank updating in order to improve the network performance in mobility scenarios where all nodes except sink nodes are moving. This enhancement helps RPL to better cope with mobility scenarios and to make faster decisions on updating next-hop neighbors. Moreover, we propose a dynamic management of control messages in order to reduce the overhead in the network. Simulation results show that our technique outperforms the standard RPL in different network configurations.