Evaluation of Asymmetric Link-Based AODV Routing Protocol for Low Power and Lossy Networks in COOJA Simulator

Route discovery for Point-to-Point (P2P) traffic flows is critical in Low-power and Lossy Networks (LLNs), especially in home and building automation applications. Although the Routing Protocol for Low-Power and Lossy Networks (RPL), standardized by the Internet Engineering Task Force (IETF), is widely used, it struggles to efficiently handle P2P flows, leading to congestion at the Destination Oriented Directed Acyclic Graph (DODAG) root and increased packet delays. The P2P-RPL protocol aims to address this issue, but neither RPL nor P2P-RPL adequately account for asymmetric wireless links in their route computations. AODV-RPL, a protocol draft adopted by the IETF's ROLL working group, offers a reactive P2P route discovery mechanism based on Ad Hoc On-demand Distance Vector Routing (AODV), operating with RPL in its storing mode. This study assesses the performance of AODV-RPL using the Cooja simulator across various network topologies and node densities, considering both symmetric and asymmetric links. Through extensive simulations, it is demonstrated that AODV-RPL outperforms traditional RPL in Packet Delivery Ratio (PDR) and delay performance for numerous source and destination pairs. However, while AODV-RPL generally improves upon traditional RPL for P2P routes, some node pairs remain where the difference in relative hop distance is minimal.