FTC-OF: Forwarding Traffic Consciousness Objective Function for RPL Routing Protocol

TLDR: Forwarding Traffic Consciousness Objective Function has been proposed, which combines three routing metrics, namely hop count, RSSI and a newly designed Forwarded Traffic Metric (FTM), and considerably reduces the power consumption.

Abstract: The rise of the Internet of Things (IoT) and the diversity of its applications make the need for a flexible routing protocol able to face several constraints very essential. In this context, the RPL protocol was designed to meet the need for IoT classified as low power and lossy networks (LLN's). RPL relies on an objective function that takes into account a metric to implement its routing strategy in the network. On the other hand, the problem consists of a single routing metric that sometimes leads to the selection of non-optimized or static routes in the network. As a consequence, two main problems emerge, the first is the congestion created in the nodes due to the high number of packets to be relayed which leads to their loss, the second is the greedy energy consumption by these nodes which can conduct to quickly degrade their batteries, thus losing and causing loss the connectivity of several nodes in the network. To remedy this problem, a novel objective function for RPL FTC-OF has been implemented in the core of the embedded operating system CONTIKI, which combines three different routing metrics, aiming to create a balanced network while considering the quality of link on a short path, namely hop count, RSSI and a newly designed metric called Forwarded Traffic Metric (FTM). The proposed method, considered as a new balancing strategy, evaluated under the COOJA emulator, outperforms ETX and Energy based RPL protocols. It shows that it increases the rate of packet delivery, considerably reduces the power consumption of the network as well as an almost perfect balance of traffic managed by the relay nodes.