RPL-Based Hybrid Hierarchical Topologies for Scalable IoT Applications

The applications built nowadays are mainly distributed, and most of them have sensors enabling them to do it. Internet of Things in the same context is solving real-world problems. Although there are challenges still like on ground scalability, efficiency, etc. and a lot of other bottlenecks, in our work here we have focused on RPL routing protocol and the potential to scale under strained networks. Some real-world application scenarios like military and agriculture build in an environment with the “strained” transmission and interference ranges, which requires the nodes to be retained as part of Destination-Oriented Directed Acyclic Graph (DODAG). The simulation study done using Contiki OS-based Cooja simulation environment on hierarchical and circular network topologies for highly scalable and strained networks shows high energy consumption and the impact on the radio duty cycle on few selected nodes of DODAG. Combining the features of hierarchical and circular network topology, we propose a hybrid hierarchical topology with multiple sinks which resembles the real-world applications. The testing and relative comparison of RPL’s Objective Functions (OFs) consists of the following parameters: Power Consumption, Radio Duty Cycle, and possible topologies. The results of the simulation study of RPL protocol show that the proposed hybrid network topology results in much stable energy consumption and radio duty cycle increasing the scale and strain on the network.