EBOF: A New Load Balancing Objective Function for Low-power and Lossy Networks

Abstract

The IPv6-based Routing Protocol for Low-Power and Lossy Networks (RPL) is a new routing protocol designed to satisfy constrained networks such as 6LoWPAN. The default route selection technique of RPL takes into account a single metric, which is unable to recognize the load balancing problem in the network. As a consequence, energy may drain rapidly from overloaded nodes, and the nodes that die first can cause a partition in the network. To resolve this problem, we propose a new RPL-compliant objective function named the Energy Balance Objective Function (EBOF). It combines two different routing metrics, which are the Expected Transmission Count (ETX) and the Child Count (CC). Then, the Destination Oriented Directed Acyclic Graph (DODAG) Information Object (DIO) message format is amended to disseminate the CC information among neighbor nodes. Two metrics are utilized to select the best path and to construct a balanced network. The proposed scheme is examined through simulation tests and evaluated against the Minimum Rank with Hysteresis Objective Function (MRHOF), the Load Balancing Model for RPL (ALABAMO), and Load Balanced Objective Function (LB-OF). The resulting analysis shows that the proposed EBOF significantly achieves the energy balance among intermediate nodes, which in turn prolongs the network lifetime.