Design and Performance Analysis of Objective Functions for RPL Routing Protocol

Standardized by Internet Engineering Task Force (IETF) working group, RPL (Routing Protocol for Low Power and Lossy networks) stands as an effective IPV6 Routing Protocol that establishes a path between any sensor and the sink wich typically collect the information generated by a wireless sensor network. For this purpose, RPL constructs a Destination Oriented Directed Acyclic Graph (DODAG), using an objective function (OF) that implements the metric being used. In particular, RPL supports the point-to-multipoint (P2MP) mode of traffic, and optionally the multipoint-to-point (MP2P) and point-to-point traffic ranges. This paper evaluates the performance of RPL considering three key parameters: network density, throughput and sink localization. We further consider the three following metrics: Expected Transmission count (ETX), Hop Count (HC) and Energy. Our simulations reveal that the number of nodes affects the parameters regardless of the scenarios. In addition, the ETX metric performs well in all scenarios in terms of Packet Delivery Ratio (PDR) and Energy metric, which turns out to have the highest energy consumption with respect to all the implemented scenarios.