An Overview on RPL Objective Function Enhancement Approaches

Abstract

RPL is an IPv6 routing protocol for Low-Power and Lossy Networks (LLNs) designed by the ROLL working group to fit challenging routing requirements of LLNS network. RPL relies on Objective Function (OF) to select best parents and then construct paths. Considering the vast areas of applications for RPL, the routing protocol was designed with a great deal of flexibility. In fact RPL does not specify any particular routing metric/constraint to be used for DAG rank computation. In this paper, we give an overview of the different approaches considered to optimize RPL OF and classify them. More specifically, we specify which metrics are considered for OF enhancement and optimal parent selection. After a comparative study, we finally discuss the proposed enhancement schemes and highlight some limitations of the existing strategies.