Performance Evaluation of Different RPL Formation Strategies

Abstract: The size of the IoT network is expanding due to advancements in the IoT field, leading to increased interest in the multi-sink mechanism. The IPv6 Routing Protocol for Low-Power and Lossy Networks (RPL) is a representative IoT protocol that focuses on the Low-Power and Lossy Networks. However, research on comparing multi-sink strategies within the RPL network is limited. Therefore, this project aims to compare three common strategies: multiple-DODAG in one instance, virtual root, and multiple-instance. Using these strategies, we design and implement RPL networks and conduct simulations in various scenarios. Five different topologies are utilized in the experiments, considering different packet loss rates. Performance evaluation of each strategy is conducted using the Cooja simulator and Contiki-NG system, with a focus on the number of RPL control packets, Packet Delivery Ratio (PDR), and energy consumption. The results indicate that both the virtual root and multiple-DODAG strategies perform well with low packet loss, while the virtual root strategy outperforms the multiple-DODAG strategy with high packet loss. Additionally, the virtual root strategy incurs slightly higher energy costs than the multiple-DODAG strategy. Furthermore, the multiple-instance strategy demonstrates poor performance in most scenarios, except for the packet delivery ratio under high packet loss conditions. Besides the analysis, potential areas for future research on the RPL’s multi-sink mechanism are finally identified.