RPL Protocol Performance Analysis Across Multiple IoT Topologies
Suneeta Mishra, Vidushi Sharma, Vimlesh Kr · 2025
The Internet of Things (IoT) network topology model is categorized as a Low-Power and Lossy Network (LLN). With the advent of IoT., the need for specialized protocols to address the unique challenges of LLNs, such as constrained nodes (e.g., battery-powered sensors), unreliable and dynamic wireless links, and scalability requirements for dense networks, became increasingly apparent. In 2012, the IETF ROLL (Routing Over Low Power and Lossy Networks) working group officially standardized RPL in RFC 6550, titled “RPL: IPv6 Routing Protocol for Low-Power and Lossy Networks.” RPL is designed to provide efficient routing solutions for LLNs across various application domains, including industrial automation, smart cities, and home automation. It employs objective functions, such as OF0 (Objective Function Zero) and MRHOF (Minimum Rank with Hysteresis Objective Function), to determine routes from source nodes to destination nodes based on metrics like ETX and energy. Previous studies on RPL were limited in their exploration of topological variations, which constrained the understanding of RPL's adaptability to different network structures. Additionally, earlier works lacked detailed analysis of hybrid topologies and did not adequately address the balance between energy consumption and routing efficiency. Performance assessments were frequently confined to a narrow set of metrics, neglecting crucial factors such as control traffic overhead, end-to-end delay and throughput, which are essential for practical IoT deployments. This study bridges these gaps by evaluating RPL under diverse topologies, proposing a novel hybrid topology, and incorporating a broader range of performance metrics for a holistic analysis. The proposed work introduces a hybrid star-tree topology, offering an innovative approach to optimize routing efficiency, by combining the hierarchical structure of the tree topology with the robustness of the star topology, the hybrid model achieves improved scalability, reduced control traffic overhead, and enhanced energy efficiency. This work also extends the evaluation of RPL to a variety of network configurations, providing comprehensive insights into its behavior under different conditions. Testing and evaluation were conducted using the Cooja simulator within the Contiki operating system and performance metrics achieved by wireshark network analyser. This paper explores the challenges encountered in IoT networks and investigates how different topologies effectively address and overcome these issues.