RPL is the IPv6 routing protocol for low-power and lossy networks, standardized by IETF in 2012 as RFC6550. Specifically, RPL is designed to be a simple and inter-operable networking protocol for resource-constrained devices in industrial, home, and urban environments, intended to support the vision of the Internet of Things with thousands of devices interconnected through multihop mesh networks. More than four-years have passed since the standardization of RPL, and we believe that it is time to examine and understand its current state. In this paper, we review the history of research efforts in RPL; what aspects have been (and have not been) investigated and evaluated, how they have been studied, what was (and was not) implemented, and what remains for future investigation. We reviewed over 97 RPL-related academic research papers published by major academic publishers and present a topic-oriented survey for these research efforts. Our survey shows that only 40.2% of the papers evaluate RPL through experiments using implementations on real embedded devices, ContikiOS and TinyOS are the two most popular implementations (92.3%), and TelosB was the most frequently used hardware platform (69%) on testbeds that have average and median size of 49.4 and 30.5 nodes, respectively. Furthermore, unfortunately, despite it being approximately four years since its initial standardization, we are yet to see wide adoption of RPL as part of real-world systems and applications. We present our observations on the reasons behind this and suggest directions on which RPL should evolve.

Challenging the IPv6 Routing Protocol for Low-Power and Lossy Networks (RPL): A Survey

Wireless networked control systems (WNCS) are composed of spatially distributed sensors, actuators, and con- trollers communicating through wireless networks instead of conventional point-to-point wired connections. Due to their main benefits in the reduction of deployment and maintenance costs, large flexibility and possible enhancement of safety, WNCS are becoming a fundamental infrastructure technology for critical control systems in automotive electrical systems, avionics control systems, building management systems, and industrial automation systems. The main challenge in WNCS is to jointly design the communication and control systems considering their tight interaction to improve the control performance and the network lifetime. In this survey, we make an exhaustive review of the literature on wireless network design and optimization for WNCS. First, we discuss what we call the critical interactive variables including sampling period, message delay, message dropout, and network energy consumption. The mutual effects of these communication and control variables motivate their joint tuning. We discuss the effect of controllable wireless network parameters at all layers of the communication protocols on the probability distribution of these interactive variables. We also review the current wireless network standardization for WNCS and their corresponding methodology for adapting the network parameters. Moreover, we discuss the analysis and design of control systems taking into account the effect of the interactive variables on the control system performance. Finally, we present the state-of-the-art wireless network design and optimization for WNCS, while highlighting the tradeoff between the achievable performance and complexity of various approaches. We conclude the survey by highlighting major research issues and identifying future research directions.

Wireless Network Design for Control Systems: A Survey

Recently, the Internet of Things (IoT) concept has attracted a lot of attention due to its capability to translate our physical world into a digital cyber world with meaningful information. The IoT devices are smaller in size, sheer in number, contain less memory, use less energy, and have more computational capabilities. These scarce resources for IoT devices are powered by small operating systems (OSs) that are specially designed to support the IoT devices’ diverse applications and operational requirements. These IoT OSs are responsible for managing the constrained resources of IoT devices efficiently and in a timely manner. In this paper, discussions on IoT devices and OS resource management are provided. In detail, the resource management mechanisms of the state-of-the-art IoT OSs, such as Contiki, TinyOS, and FreeRTOS, are investigated. The different dimensions of their resource management approaches (including process management, memory management, energy management, communication management, and file management) are studied, and their advantages and limitations are highlighted.

A Survey on Resource Management in IoT Operating Systems

In the last few years, the Internet of Things (IoT) has proved to be an interesting and promising paradigm that aims to contribute to countless applications by connecting more physical “things” to the Internet. Although it emerged as a major enabler for many next-generation applications, it also introduced new challenges to already saturated networks. The IoT is already coming to life especially in healthcare and smart environment applications adding a large number of low-powered sensors and actuators to improve lifestyle and introduce new services to the community. The Internet Engineering Task Force (IETF) developed RPL as the routing protocol for low-power and lossy networks (LLNs) and standardized it in RFC6550 in 2012. RPL quickly gained interest, and many research papers were introduced to evaluate and improve its performance in different applications. In this paper, we present a discussion of the main aspects of RPL and the advantages and disadvantages of using it in different IoT applications. We also review the available research related to RPL in a systematic manner based on the enhancement area and the service type. In addition to that, we compare related RPL-based protocols in terms of energy efficiency, reliability, flexibility, robustness, and security. Finally, we present our conclusions and discuss the possible future directions of RPL and its applicability in the Internet of the future.

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RPL-Based Routing Protocols in IoT Applications: A Review

Advanced metering infrastructure (AMI) is becoming a vital part of utility distribution networks, allowing the development of smart cities. AMI consists of smart electric, gas, and water meters, and the devices are very limited in terms of battery, processing power, and memory. The deployment and operational needs of energy-constrained network infrastructures in smart water and gas metering systems require the use of routing mechanisms that consider energy consumption, minimize energy use, and prolong network lifetime. An efficient routing metric is needed for energy-constrained devices. In this paper, we propose an energy- and congestion-aware routing metric for smart meter networks to be deployed in smart cities. The proposed metric is an adaptive parent node selection mechanism that considers the residual energy and queue utilization of neighboring nodes. Minimizing power consumption will enhance network lifetime. The proposed scheme was evaluated with the Cooja Simulator 3.0 using random and grid topology. The simulation results show greater network performance in terms of average power consumption and packet delivery ratio.

Energy and Congestion-Aware Routing Metric for Smart Grid AMI Networks in Smart City

RPL is an IPv6 routing protocol for low-power and lossy networks (LLNs) designed to meet the requirements of a wide range of LLN applications including smart grid AMIs, industrial and environmental monitoring, and wireless sensor networks. RPL allows bi-directional end-to-end IPv6 communication on resource constrained LLN devices, leading to the concept of the Internet of Things (IoT) with thousands and millions of devices interconnected through multihop mesh networks. In this article, we investigate the load balancing and congestion problem of RPL. Specifically, we show that most of the packet losses under heavy traffic are due to congestion, and a serious load balancing problem appears in RPL in terms of routing parent selection. To overcome this problem, this article proposes a simple yet effective queue utilization based RPL ( QU-RPL ) that achieves load balancing and significantly improves the end-to-end packet delivery performance compared to the standard RPL. QU-RPL is designed for each node to select its parent node considering the queue utilization of its neighbor nodes as well as their hop distances to an LLN border router (LBR). Owing to its load balancing capability, QU-RPL is very effective in lowering queue losses and increasing the packet delivery ratio. We implement QU-RPL on a low-power embedded platform, and verify all of our findings through experimental measurements on a real testbed of a multihop LLN over IEEE 802.15.4. We present the impact of each design element of QU-RPL on performance in detail, and also show that QU-RPL reduces the queue loss by up to 84 percent and improves the packet delivery ratio by up to 147 percent compared to the standard RPL.

Load Balancing Under Heavy Traffic in RPL Routing Protocol for Low Power and Lossy Networks

Dt-rpl

One of the most important and recurrent tasks in managing a store is to provide accurate information of products to customers by maintaining up-to-date price tags of every item. Till today, however, updating price tags is done manually in most markets, which is labor-intensive, time-consuming, and error-prone. Adopting wirelessly reconfigurable electronic price tags could be of significant benefit to this problem. A key requirement of such a system, then, is to establish a robust, reliable, and scalable wireless communication network while spending minimal energy on thousands of densely-deployed and battery-powered price tags. In this work, we present a comprehensive study of electronic shelf labeling (ESL) system including its design and real-world deployment experiences. While the overall design turns out to be relatively straightforward, our preliminary study using 1000 real commercial e-tags reveals technical challenges in reliable and low-power wireless communication with ultra-high node density in scatter-rich indoor environments. To address the problem, we adopt multi-radio and multi-channel diversity techniques which need to modify only the gateways but significantly improve overall system performance. Our evaluation from a real-world deployment of 550 tags at an actual convenience store shows that our proposal achieves 98.51% network connectivity, 590 ms average latency for price updates, and over 5 years of e-tag lifetime. ESL system is part of the upcoming smart market era, and we see this work as a practical industrial application case study of Internet of Things technologies.

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Low-Power Wireless With Denseness: The Case of an Electronic Shelf Labeling System—Design and Experience

This paper tackles the mobile routing issues in low-power and lossy networks (LLNs). The IPv6 standard routing protocol for LLNs, termed IPv6 routing protocol for low-power and lossy networks (RPL), has mostly been investigated in static LLNs and it has no explicit mechanism to support mobility. In addition, there is no mobile routing protocol that works well in mobile LLNs. Considering the importance of mobility support in many LLN applications, this work designs and implements MobiRPL, an adaptive, robust, and received signal strength indicator (RSSI)-based mobile routing scheme based on the RPL standard. To cope with network dynamics, the MobiRPL design focuses more on maintaining reliable routing topology than on minimizing energy consumption. This design choice significantly improves reliability while maintaining the acceptable energy consumption of mobile LLNs. We implement MobiRPL on Contiki OS, and evaluate its effectiveness extensively through Cooja simulation and testbed experiments. Our results from the testbed show that MobiRPL improves mobile nodes' packet delivery ratio by 11.3% compared to RPL and reduces the energy consumption of mobile nodes by 73.3% compared to the baseline scheme, i.e., the lightweight on-demand ad-hoc distance-vector routing protocol — next generation (LOADng). 

https://ieeexplore.ieee.org/ielx7/5449605/9826583/09718363.pdf

MobiRPL: Adaptive, robust, and RSSI-based mobile routing in low power and lossy networks

This demo presents MobiRPL that improves RPL for reliable routing under a mobility scenario in low- power and lossy networks In the considered mobility scenario, mobile devices participate in routing/forwarding MobiRPL has four new components that RPL does not have We implement MobiRPL on Contiki OS This demo will present an operation example of MobiRPL using Cooja simulator

Hongchan Kim

Papers

Load Balancing Under Heavy Traffic in RPL Routing Protocol for Low Power and Lossy Networks

Dt-rpl

Low-Power Wireless With Denseness: The Case of an Electronic Shelf Labeling System—Design and Experience

MobiRPL: Adaptive, robust, and RSSI-based mobile routing in low power and lossy networks

Demo: Mobility Enhanced RPL for General Mobility Scenarios