A Comprehensive Study of multicast Routing Protocols in the Internet of Things

Abstract

IP multicast is a desired communication feature in the Internet of Things (IoT) as it provides noticeable resource savings, especially for Low-power and Lossy Networks (LLNs). Indeed, multicast allows cost-, energy-, and time-efficient networking for a multitude of LLN applications ranging from over-the-air programming and information sharing to device configuration and resource discovery. In this context, several multicast routing protocols have been recently proposed for LLNs including Stateless multicast RPL Forwarding (SMRF), Enhanced SMRF (ESMRF), Bi-Directional multicast Forwarding Algorithm (BMFA), and multicast Protocol for LLNs (MPL). Nevertheless, each protocol has been evaluated under different conditions, topologies, and traffic flow, which prevents making comprehensive comparisons of their characteristics and performance. In this paper, we provide an overview of recent LLN multicast protocols followed by a multidimensional performance evaluation of the most popular ones to extract their advantages and drawbacks under different traffic conditions, routing scenarios, and network topologies. Obtained results from extensive realistic simulations using Cooja show that, although each protocol is dominant under specific conditions, MPL remains the best in terms of packet delivery ratio in all scenarios at the expense of extra energy consumption, which requires new resourcesaware multicast solutions for the IoT.