Low Power And Lossy Networks Research Articles

RPL-Based Routing Protocols in IoT Applications: A Review

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.

Traffic-aware auto-configuration protocol for service oriented low-power and lossy networks in IoT

Many diversified services can be offered by smart objects, referred to herein by nodes, in low-power and lossy networks (LLNs) contributing to the Internet of Things (IoT). A distributed naming and registration system, complying with the Internet protocol standard, is needed for unique identification of these nodes and their provided services in many areas such as monitoring and remote control. Due to the high expected number of IoT nodes, manual configuration is not practical, and an efficient auto-configuration mechanism is essential. Although the multicast domain name system (mDNS) is the most common distributed naming protocol nowadays, it is not optimized for constrained LLN nodes in IoT. This work proposes enhanced mDNS (E-mDNS) which augments mDNS with three proposed enhancements: the persistent-based selection stage, the simultaneous start-up enhancement, and the announcement suppression mechanism. Using the Cooja emulation platform, we evaluate both the mDNS and E-mDNS for a wide range of conditions and network sizes, and produce a large array of performance figures that includes number of control packets, energy consumption for CPU and radio transmissions, memory footprint, and others. Through the evaluation of the fairness index for a wide range of number of nodes, we demonstrate that E-mDNS provides better load balancing for the collection of nodes in the network relative to mDNS. Furthermore, results indicate that while E-mDNS produces a memory footprint in RAM that is only 4.2% more than that for mDNS, E-mDNS manages to significantly reduce the number of control packets by an average of 34.8% for the considered range of network size. Accordingly, the corresponding reduction in energy consumption for radio transmissions and CPU is 46.7% and 47.5%, respectively. The evaluation shows that these reductions are greater for larger number of nodes.

Fuzzy Sets Based Cluster Routing Protocol For Internet of Things

Increasing the lifetime of low power and lossy networks (LLN) is a major challenge, as the nodes have low power, low memory, and low processing capacity. Clustering is a technique used to minimize the energy consumption of sensor nodes. This article proposes a fuzzy sets-based cluster routing protocol (FC-RPL) to extend the network lifetime in LLN. It has three processes: cluster formation, cluster head selection, and cluster head parent selection. It forms the clusters based on the Euclidean distance. It applies the fuzzy set over the metrics residual energy, number of neighbors and centrality, to select the cluster head in each cluster. The cluster head node chooses the best parent node in the DODAG for data transfer. The simulation is performed using COOJA simulator. The simulation result shows that FC-RPL extends the network lifetime by 15-25% and increases the packet delivery ratio by 2-6%.

A Survey on Congestion Control for RPL-Based Wireless Sensor Networks.

RPL (IPv6 routing protocol for low power and lossy networks) proposed by the IETF (Internet Engineering Task Force) ROLL (routing over low-power and lossy networks) working group is a de facto standard routing protocol for IoT environments. Since the standardization was proposed, RPL has been extensively improved for diverse application scenarios and environments. Congestion control is one of the most important reasons why RPL has been improved. In an LLN (low power and lossy network), congestion may even lead to network lifetime reduction. In resource-constrained networks where end-to-end congestion control is not feasible, RPL should play a more crucial role in congestion control. In this survey, we review the RPL schemes proposed for congestion control and load-balancing and discuss future research directions.

A Comprehensive Survey on RPL: Evolution and Challenges

LLNs (Low Power and Lossy Networks) are becoming hot research topics due to challenges posed by their limited battery life, computing power, memory and transmission power. LLNs require a routing protocol which can perform efficiently with their limitations. IETF has come up with RPL as standard routing protocol for LLNs. It builds energy efficient network. But it also has major limitations and several research have happened to overcome the same. This paper is survey of RPL challenges and recent research on RPL extensions. Major RPL limitations include packet loss under noisy scenario, increased DODAG depth causing high energy consumption. TTA (Trickle Timer Algorithm) is important part of RPL. It is used to manage control messages flow. Limitation of trickle algorithm results in problem of short time for listening and it can make few nodes crave for delay and higher latency. E-Trickle is proposed to overcome the listen only period, improve convergence time and energy consumption. QOI (Quality of Information) aware RPL reduces the energy consumption with less data transmission. RPL operates under one sink. Entire data flows towards the single sink. RPL doesn’t specify when, where and how more number of sinks need to be used. Dynamic rescue sink is RPL enhancement built with real timetracking of nodes’ performance in RPL networks to propose new sinks when required. AMI (Advanced metering infrastructure) is one of the application in smart grid for connecting smart metering devices at homes. It is critical to have efficient routing protocol for AMI as the smart meter nodes are resource constrained. AMI with high density networks suffer from high packet loss, network congestion retransmissions, increased latency, control traffic overhead and power consumption. LQE (Link Quality Estimation) influences quality of selected route and energy consumption. RL-probe measures link quality precisely with small overhead and energy consumption. RL-probe reduces packet loss by reacting to link quality variations and link failures due to mobility. Communication overhead needs to be as minimal as possible inLLNs with limited resources. Adaptive timing model uses dynamic method to decide frequency of executing objective function to construct DODAG based on degree of surrounding changes and reduces the control messages overhead. Objective is to bring down the PLR (packet loss ratio), overhead of control messages and battery usage. RPL doesn’t give good results for high throughput and changes in network conditions. This prevents use of RPL in high speed sensors and mobile sensing applications. BRPL is extension to RPL which combines RPL objective function (OF) with back pressure routing to handle dynamic traffic load and mobility.

Routing Protocols for Low Power and Lossy Networks in Internet of Things Applications.

The emergence of the Internet of Things (IoT) and its applications has taken the attention of several researchers. In an effort to provide interoperability and IPv6 support for the IoT devices, the Internet Engineering Task Force (IETF) proposed the 6LoWPAN stack. However, the particularities and hardware limitations of networks associated with IoT devices lead to several challenges, mainly for routing protocols. On its stack proposal, IETF standardizes the RPL (IPv6 Routing Protocol for Low-Power and Lossy Networks) as the routing protocol for Low-power and Lossy Networks (LLNs). RPL is a tree-based proactive routing protocol that creates acyclic graphs among the nodes to allow data exchange. Although widely considered and used by current applications, different recent studies have shown its limitations and drawbacks. Among these, it is possible to highlight the weak support of mobility and P2P traffic, restrictions for multicast transmissions, and lousy adaption for dynamic throughput. Motivated by the presented issues, several new solutions have emerged during recent years. The approaches range from the consideration of different routing metrics to an entirely new solution inspired by other routing protocols. In this context, this work aims to present an extensive survey study about routing solutions for IoT/LLN, not limited to RPL enhancements. In the course of the paper, the routing requirements of LLNs, the initial protocols, and the most recent approaches are presented. The IoT routing enhancements are divided according to its main objectives and then studied individually to point out its most important strengths and weaknesses. Furthermore, as the main contribution, this study presents a comprehensive discussion about the considered approaches, identifying the still remaining open issues and suggesting future directions to be recognized by new proposals.

TAiM: TCP assistant-in-the-middle for multihop low-power and lossy networks in IoT

We investigate the performance of TCP over multihop many-to-one wireless low-power and lossy networks (LLNs), and present TCP assistant-in-the-middle (TAiM) to improve TCP fairness among LLN endpoints without sacrificing aggregate throughput nor end-to-end backward compatibility. TAiM exploits the fact that RTT over LLN is significantly higher, and more variable, than wired or WiFi networks due to unique characteristics of LLN. TAiM intervenes in the middle of TCP communication only at the LLN border router (LBR), and delicately manipulates the RTT of the passing flows to achieve its goal, but does not infringe anything of packet nor operation of existing protocols. TAiM is adaptive and flexible to network status, and does not require any modifications to the TCP/IPv6 stack at the endpoints. We implement TAiM solely in a Linux-based LBR, and perform experiments on two 30-nodes TelosB testbeds running BLIP/TinyRPL stack in TinyOS. Our experiment results show that TAiM helps TCP to operate fairly and efficiently while maintaining total throughput and end-to-end compatibility.

A Novel Approach for RPL Assessment Based on the Objective Function and Trickle Optimizations

The ROLL working group proposed the RPL (IPv6 routing protocol for low-power and lossy networks) to respond to the requirements of low-power and lossy networks (LLNs). In this paper, we propose a new approach to assess the RPL performances based on its main components, namely, the objective function (OF) and the trickle algorithm. To this end, we compare between the RPL-EC (RPL based combined ETX and energy consumption) and the RPL-FL (RPL based on the flexible trickle algorithm). This paper compares the two implementations to assess the weight of each proposed improvement against the standard RPL. The results show that RPL performances are greatly influenced by the change of both the objective function and trickle algorithm. RPL-FL provides best values in terms of overhead, packet delivery ratio (PDR), and energy consumption, while RPL-EC acts better with the convergence time and the network lifetime compared to the standard RPL.

Routing with Energy Threshold for WSN-IoT Based on RPL Protocol

Internet of Things (IoT) enables things to have connectivity through the internet. The number of things is growing fast and has to be uniquely identified through the Internet to communicate with other things. In Wireless Sensor Networks (WSNs) each node can be considered as a thing. WSN node resources are very limited due to the need to communicate using low power and usually through unreliable links. Such limitations need an energy efficient routing protocol. WSN is considered as a type of Low power and Lossy Network (LLN). The routing protocol for low power and lossy network (RPL) is being adopted for LLN and has been standardized to enable connectivity of WSN over IoT. RPL constricted a topology similar to tree topology. Nodes in RPL optimized its path using an objective function (OF). OF depends on different node/link metrics in the optimization process. In this paper, an Energy Threshold RPL (ETRPL) protocol is proposed. ETRPL depends on a new objective function to enhance energy consumption of RPL protocol by taking into account the remaining energy of the preferred parent node. ETRPL is implemented using Cooja simulator. The results show that ETRPL provides an increase in the remaining energy of at least 87.4% for a small area with high number of nodes. ETRPL also performed better with regards to Time Delay, Packet Reception Ratio, and the number of dead nodes in a small area. For a large area, the performance is not encouraging. Thus the proposed ETRPL protocol is useful for IoT networks with relatively small areas.

A Mechanism for Securing IoT-enabled Applications at the Fog Layer

The Internet of Things (IoT) is an emerging paradigm branded by heterogeneous technologies composed of smart ubiquitous objects that are seamlessly connected to the Internet. These objects are deployed as Low power and Lossy Networks (LLN) to provide innovative services in various application domains such as smart cities, smart health, and smart communities. The LLN is a form of a network where the interconnected devices are highly resource-constrained (i.e., power, memory, and processing) and characterized by high loss rates, low data rates, and instability in the communication links. Additionally, IoT devices produce a massive amount of confidential and security-sensitive data. Various cryptographic-based techniques exist that can effectively cope with security attacks but are not suitable for IoT as they incur high consumption of resources (i.e., memory, storage and processing). One way to address this problem is by offloading the additional security-related operations to a more resourceful entity such as a fog-based node. Generally, fog computing enables security and analysis of latency-sensitive data directly at the network’s edge. This paper proposes a novel Fog Security Service (FSS) to provide end-to-end security at the fog layer for IoT devices using two well-established cryptographic schemes, identity-based encryption, and identity-based signature. The FSS provides security services such as authentication, confidentiality, and non-repudiation. The proposed architecture would be implemented and evaluated in an OPNET simulator using a single network topology with different traffic loads. The FSS performed better when compared with the APaaS and the legacy method.

Adaptive Downward/Upward Routing Protocol for Mobile-Sensor Networks

Recently, mobility support has become an important requirement in various Wireless Sensor Networks (WSNs). Low-power and Lossy Networks (LLNs) are a special type of WSNs that tolerate a certain degree of packet loss. However, due to the strict resource constraints in the computation, energy, and memory of LLNs, most routing protocols only support static network topologies. Data collection and data dissemination are two basic traffic modes in LLNs. Unlike data collection, data dissemination is less investigated in LLNs. There are two sorts of data-dissemination methods: point-to-multipoint and point-to-point. In this paper, we focus on the point-to-point method, which requires the source node to build routes to reach the destination node. We propose an adaptive routing protocol that integrates together point-to-point traffic and data-collection traffic, and supports highly mobile scenarios. This protocol quickly reacts to the movement of nodes to make faster decisions for the next-hop selection in data collection and dynamically build routes for point-to-point traffic. Results obtained through simulation show that our work outperforms two generic ad hoc routing protocols AODV and flooding on different performance metrics. Results also show the efficiency of our work in highly mobile scenarios with multiple traffic patterns.

Mobility support enhancement for RPL with multiple sinks

In recent years, low power and lossy networks (LLNs) have attracted the attention of researchers. They typically operate with strict resource constraints in communication, computation, memory, and energy. Routing protocol for LLNs (RPL) is an ad-hoc distance vector routing protocol for LLNs that adapts IPv6 and runs on top of IEEE 802.15.4 standard. Although RPL was originally designed for static topologies, for many applications mobility support has been a major requirement in LLNs. In addition, part of these applications requires multiple sink nodes rather than one sink node. This is due to the fact that in a data collection wireless sensor network (WSN), only one sink easily leads to a faster energy depletion, more packet loss, higher latency, and smaller network range. Deploying multiple sinks in the network can help solve these problems. This paper focuses on addressing mobility support in RPL with multiple sinks. We propose an enhancement based on signal strength monitoring and rank updating in order to improve the network performance in mobility scenarios where all nodes except sink nodes are moving. This enhancement helps RPL to better cope with mobility scenarios and to make faster decisions on updating next-hop neighbors. Moreover, we propose a dynamic management of control messages in order to reduce the overhead in the network. Simulation results show that our technique outperforms the standard RPL in different network configurations.

An Efficient Design of RPL Objective Function for Routing in Internet of Things using Fuzzy Logic

The nature of the Low power and lossy networks (LLNs) requires having efficient protocols capable of handling the resource constraints. LLNs consist of networks that connect different type of devices which has constraints resources such as energy, memory and battery life. Using the standard routing protocols such as Open Shortest Path First (OSPF) is inefficient for LLNs due to the constraints that LLNs need. So, IPv6 Routing Protocol for Low-Power and Lossy Networks (RPL) was developed to accommodate these constraints. RPL is a distance vector protocol that used the object functions (OF) to define the best tree path. However, choosing a single metric for the OF found to be unable to accommodate applications requirements. In this paper, an enhanced (OF) is proposed namely; OFRRT-FUZZY relying on several metrics combined using Fuzzy Logic. In order to overcome the limitations of using a single metric, the proposed OFRRT-FUZZY considers node and link metrics. Namely, Received Signal Strength Indicator (RSSI), Remaining Energy (RE) and Throughput (TH). The proposed OFRRT-FUZZY is implemented under Cooja simulator and then results were compared with OF0, MHROF in order to find which OF provides more satisfactory results. And simulation results show that OFRRT-FUZZY outperformed OF0 and MHROF.

A Survey of Limitations and Enhancements of the IPv6 Routing Protocol for Low-Power and Lossy Networks: A Focus on Core Operations

Driven by the special requirements of the Lowpower and Lossy Networks (LLNs), the IPv6 Routing Protocol for LLNs (RPL) was standardized by the IETF some six years ago to tackle the routing issue in such networks. Since its introduction, however, numerous studies have pointed out that, in its current form, RPL suffers from issues that limit its efficiency and domain of applicability. Thus, several solutions have been proposed in the literature in an attempt to overcome these identified limitations. In this survey, we aim mainly to provide a comprehensive review of these research proposals assessing whether such proposals have succeeded in overcoming the standard reported limitations related to its core operations. Although some of RPL weaknesses have been addressed successfully, the study found that the proposed solutions remain deficient in overcoming several others. Hence, the study investigates where such proposals still fall short, the challenges and pitfalls to avoid, thus would help researchers formulate a clear foundation for the development of further successful extensions in future allowing the protocol to be applied more widely.

Network Performance Enhancement of Multi-sink Enabled Low Power Lossy Networks in SDN Based Internet of Things

Software Defined Network (SDN) brought revolution in the network field with the partnership of Academia and Industry. SDN bridges the gap to overcome issues of IoT deployment, optimization and better utilization of network resources. The escalation in resource congestion in Wireless Sensor Networks (WSNs) can usually lead to scalability, data computation or storage, and energy efficiency problems with only a single sink node for data acquisition. Internet of Things (IoT) has resource and energy constraints for WSN devices. Low Power and Lossy Networks (LLNs) ought to be optimized for traffic with multiple sinks. RPL routing has constraints to support this approach. However, RPL inherits the ability to offer features like Auto-Configuration, Self-Healing, Loop avoidance, and detection. These features of RPL can be transformed into the improved performance of a WSN by increasing the number of sinks with a linear increase of data transmitting nodes in the network. Further, to mitigate the escalated computing needs, edge computing has emerged as a new paradigm to resolve SDN-enabled IoT and localized computing needs. This study proposes an SDN-based solution to the interconnectivity of resource constraint LLN devices with edge computing routers in mesh and cluster topological scenario using RPL as IoT routing protocol. Performance evaluation concerning different routing metrics and objective functions: Minimum Rank with Hysteresis Function (MRHOF) and Zero (OF0) are analyzed. COOJA simulator is used for emulation of random as well as linear grid topologies for the creation of WSN static nodes. Simulation results confirm that the gradual increase of a number of nodes from 16, 32, 48, 64 and a simultaneous increase in sinks nodes as 1, 2, 3, 4 respectively in LLN network reflects the desired advantages with the stable network.

E2V: Techniques for Detecting and Mitigating Rank Inconsistency Attack (RInA) in RPL based Internet of Things

The Internet of Things (IoT) is a network of physical devices in which smart objects are interconnected that enable to collect and exchange the information via the internet. These devices are resource constrained and connected in the Low power and Lossy Networks (LLNs). Due to this nature, the RPL (IPv6 Routing Protocol for Low power and Lossy networks) is primarily designed for the resource constrained devices. But, this RPL undergoes various types of routing attacks. This paper considered the Rank Inconsistency Attack (RInA), which is illegitimately change the rank value and makes the network vulnerable. The proposed architecture E2V has three phases such as rank calculation, substantiation and malicious node elimination. The ultimate aim of E2V method is to detect and mitigate the RInA attack which includes sinkhole, selective forwarding and blackhole attacks. This system also identifies rank inconsistency based on the energy of each node. Hence, this approach enhances the secure routing in RPL based Internet of Things.

Parallel Rendezvous-Based Association for IEEE 802.15.4 TSCH Networks

The time-slotted channel hopping (TSCH) mode of the standard IEEE 802.15.4 provides medium access control for most low-power and lossy network (LLN) applications in the Internet of Things. TSCH creates a synchronized mesh network capable of delivering data packets in a reliable and timely manner. The standard defines a scan mechanism to allow nodes to detect the presence of a TSCH network and to associate to it. However, the time required to do so can be long, which causes excessive energy consumption, as nodes that are trying to associate stay awake during this process. In this paper, we present a rendezvous-based algorithm for TSCH association called PRV-TSCH that significantly reduces the time required for going through this process. The algorithm uses the principle of parallel rendezvous to allow nodes to associate to a TSCH network in a very short time. The interaction between the IPv6 Routing Protocol for LLNs and the time to associate to the TSCH network is also studied. The results of extensive simulation experiments and a mathematical model demonstrate that PRV-TSCH outperforms the purely passive scan proposed by the standard in terms of the time and energy required to associate to a TSCH network.

A Novel RPL Algorithm Based on Chaotic Genetic Algorithm.

RPL (routing protocol for low-power and lossy networks) is an important candidate routing algorithm for low-power and lossy network (LLN) scenarios. To solve the problems of using a single routing metric or no clearly weighting distribution theory of additive composition routing metric in existing RPL algorithms, this paper creates a novel RPL algorithm according to a chaotic genetic algorithm (RPL-CGA). First of all, we propose a composition metric which simultaneously evaluates packet queue length in a buffer, end-to-end delay, residual energy ratio of node, number of hops, and expected transmission count (ETX). Meanwhile, we propose using a chaotic genetic algorithm to determine the weighting distribution of every routing metric in the composition metric to fully evaluate candidate parents (neighbors). Then, according to the evaluation results of candidate parents, we put forward a new holistic objective function and a new method for calculating the rank values of nodes which are used to select the optimized node as the preferred parent (the next hop). Finally, theoretical analysis and a series of experimental consequences indicate that RPL-CGA is significantly superior to the typical existing relevant routing algorithms in the aspect of average end-to-end delay, average success rate, etc.

New lightweight mitigation techniques for RPL version number attacks

This paper presents two lightweight mitigation techniques for RPL Version Number Attacks (VNA) which affect the performance of IPv6-connected Low Power and Lossy Networks (LLNs) detrimentally. In RPL VNA, an attacker maliciously changes the version number of the network and thus increases delay and control message overhead and reduces network lifetime and packet delivery ratio. Simple yet effective mitigation mechanisms proposed in this paper promise significant performance improvements in an RPL network under attack. By means of the proposed techniques, the delay caused by the attacker can be shortened up to 87%, the average power consumption can be reduced up to 63%, the control message overhead can be lowered up to 71% and the data packets delivery ratio can be increased up to 86%. The proposed techniques, while allowing the ordinary RPL operation, trade off the mitigation performance against the resource overheads and thus allow network administrators to choose the right scheme for their RPL network.

TPAL: A Protocol for Node Authentication in IoT

Secure communication in Low power and Lossy Network (LLN) requires the authentication of the identities of nodes for that node to join the network. Since LLN may consist of many different nodes, where some nodes may contain sensitive and subtle information such as military data, monitoring data, or health data, that node needs to be authenticated before it can deliver any data packet. Even though LLN uses an Internet connection, current authentication for Internet protocols cannot be adopted directly into LLN due to LLN’s limited resources. LLN relies on the authentication provided by Routing Protocol for LLN (RPL), which is based on symmetric cryptography. Nevertheless, RPL reserves a mode for future work in terms of public cryptography. In this study, we propose an authentication protocol for LLN that utilizes Elliptic Curve Cryptography (ECC) called as TPAL.