This study highlights the importance of Wireless Sensor Networks (WSNs) in the Industrial Internet of Things (IIoT). It explores the key role played by the RPL protocol in routing data in industrial environments. It examines the characteristics and limitations of WSNs, including limited processing capacity and data management, as well as the challenges associated with reliability and latency in the context of the Internet of Things (IoT), WSNs, and 5G. The paper presents a systematic review that establishes a starting point for further research to determine the most commonly used metrics in RPL-based protocols designed in IIoT applications with 5G. How have these metrics been addressed in the literature? What are the future trends in terms of measuring these metrics?This work will likely contribute to advancing the development of latency-reliability solutions in the RPL protocol. Focusing on EED, ETX, and EC metrics can improve the efficiency of 5G networks in IIoT by enabling better measurement and management of network traffic, which may contribute to quality of service and reduce response times.