Academic literature on the topic 'RPL (Routing Protocol for Low­Power and Lossy Networks)'

Wireless Sensor Networks (WSNs) are being widely employed in industry, where the traditional wired communication infrastructure for control can be efficiently replaced by wireless sensors. In control applications, a low delay and a reduced jitter to send information from a plant to the controller is usually required so that the control system can act correctly and lead the plant to the desired state. In this thesis, we investigate the RPL routing protocol for WSNs in industrial control applications. RPL is a networking protocol currently being proposed by the working group Routing Protocol over Low Power and Lossy network (ROLL) of the Internet Engineering Task Force (IETF) and is mostly based on the beaconless IEEE 812.15.4 medium access control (MAC) protocol. One of the essential metric used by RPL to build a route is the delay needed to send packets from the node source to the destination. However, in the current standardization draft, such a delay is computed without considering the effects of the medium access control layer. In this thesis, we investigate the stability of the delay to route information. By the software OMNET++, we simulate the RPL protocol, where the MAC layer is implemented according to the IEEE 802.15.4 and the RPL is implemented at the network layer according to the current release of the standard. The simulator allows us to characterize the delay as function of the traffic load and network topology. By simulations, we show that there is a strong connection between the MAC and the routing. The results show that the delay introduced by the CSMA/CA influences significantly the RPL routing algorithm. We note that nodes change often their best parent along the routing path and that RPL is not stable delay-wise. Moreover, we compare the simulation results to an analytical model of the delay induced by the MAC that has been recently proposed in the literature. To improve the routing stability and alleviate the RPL jitter, a method based in this analytical model is then suggested.

Wireless Sensor Networks (WSNs) have become increasingly important. These networks comprise sensor and actuator nodes that enable intelligent monitoring and control applications in a wide spectrum of environments including smart cities, home automation, remote health and precision agriculture to mention a few. In certain IETF circles, networks of these characteristics are called Low Power and Lossy Networks (LLNs). Whereas most LLN protocol architectures were born without native IP support, there exists a tendency in the market towards IP convergence, since IP-based LLNs offer an open and tandardized way of connecting LLNs to the Internet, thus nabling the Internet of Things (IoT). Since most LLN configurations are multihop, and thus a routing protocol is required, the IETF created the Routing Over Low power and Lossy networks (ROLL) working group, which decided to develop a new routing protocol called IPv6 Routing Protocol for LLNs (RPL). RPL was specifically designed to meet the requirements of LLNs and is a central component of the IETF protocol suite for the IoT. Since RPL has already been deployed in millions of nodes, it is fundamental to characterize its properties, evaluate the influence of its main parameters and options on network performance, and analyze performance improvement possibilities. This PhD thesis presents the following original contributions in this field: 1. Evaluation of the influence of the main RPL parameters on the network convergence process over IEEE 802.15.4 multihop networks, in terms of network characteristics such as size and density. In addition, a mechanism that leverages an option available in RPL for accelerating network convergence has been proposed and evaluated. This study provides a guideline for configuring and selecting adequately crucial RPL parameters and mechanisms for achieving high network convergence performance, as well as a characterization of the related performance trade-offs. 2. Development of an analytical model for estimating the network convergence time of RPL in a static chain topology network of IEEE 802.15.4 nodes, in the presence of bit errors. Results show the scenarii in terms of BER and chain topology length that may dramatically degrade performance experienced by a user. The model provides a lower bound on the network convergence time for a random topology network. 3. Development of an analytical tool to estimate the number of control messages transmitted in a random topology static network which uses the Trickle algorithm (a transmission scheduling algorithm used in RPL) under steady state conditions. Results show the accuracy of the model, which can be used for both synchronous and asynchronous networks. The slight difference in performance between these two network configurations is discussed and illustrated. 4. Theoretical evaluation of the route change latency incurred by RPL when 6LoWPAN Neighbor Discovery (ND) is used. On this basis, a study on the impact of the relevant 6LoWPAN ND and RPL parameters on path availability and the trade-off between path availability and message overhead, has been carried out. 5. Development of a RPL simulator for OMNeT++ using the MiXiM framework.<br>La importància de les Wireless Sensor Networks (WSNs) ha estat creixent significativament en els darrers anys. Aquestes xarxes comprenen node sensors i actuadors que possibiliten aplicacions de control i monitorització en un ampli ventall d'entorns, incloent les ciutats intel·ligents, automatització residencial, etc. En alguns cercles de l'IETF, aquestes xarxes són anomenades Low Power and Lossy Networks (LLNs). La majoria d'arquitectures de protocols van néixer sense suport natiu per a IP, per ha existit recentment una tendència en el mercat envers la convergència IP, ja que les LLN basades en IP ofereixen una manera oberta i estandaritzada de connectar LLNs a Internet, tot creant la Internet de les Coses. Atès que moltes configuracions de LLNsn multisalt, i per tant es requereix un protocol d'encaminament, l'IETF va crear el Routing Over Low power and Lossy networks (ROLL) working group, que va decidir dissenyar un nou protocol anomenat IPv6 Routing Protocol for LLNs (RPL). RPL va ser específicament dissenyat per complir amb els requeriments de les LLNs i és un component central de la pila de protocols de l'IETF per a la Internet de les Coses. Atès que RPL ha estat desplegat en milions de nodes, és fonamental caracteritzar les seves propietats, avaluar la influència dels seus paràmetres principals i opcions en el rendiment, i analitzar les possibilitats de millora del protocol. Aquesta tesi presenta les següents contribucions originals en aquest camp: 1. Avaluació de la influència dels principals paràmetres de RPL en el procés de convergència de la xarxa en xarxes IEEE 802.15.4, en termes de característiques com la mida i la densitat de la xarxa. A més a més, s'ha proposat i avaluat un mecanisme que utilitza una opci disponible en el RPL per a accelerar la convergència de xarxa. Aquest estudi proporciona una guia per configurar i escollir adequadament paràmetres crucials del protocol RPL per tal d'assolir una ràpida convergència de xarxa, això com una caracteritzaci dels compromisos relacionats. 2. Desenvolupament d'un model analátic per estimar el temps de convergència de xarxa de RPL en una topologia de xarxaestàtica en cadena de nodes IEEE 802.15.4, en presència d'errors. Els resultats mostren els escenaris en termes de BER i mida de la cadena que poden degradar les prestacions percebudes per l'usuari. El model proporciona una fita inferior del temps de convergència de xarxa per a una topologia aleatòria. 3. Desenvolupament d'una eina analítica per estimar el nombre de missatges de control transmesos en una xarxa de topologia aleat ria i estàtica on s'usa l'algoritme Trickle (algoritme de planificació i control de les transmissions emprat en RPL), en condicions de règim permanent. Els resultats mostren la precisió del model, que pot ser emprat en xarxes síncrones i asíncrones. La lleugera diferència de prestacions entre un escenari i l'altre és discutida i il·lustrada. 4. Avaluació teòrica del temps de canvi de ruta de RPL quan s'usa 6LoWPAN Neighbor Discovery (ND). En base a aixó , es realitza un estudi de l'impacte dels paràmetres rellevants de RPL i 6LoWPAN ND en la disponibilitat de cambi el compromís amb l'overhead de missatges. 5. Desenvolupament d'un simulador de RPL per a OMNeT++ usant el MiXiM framework

Dissertação de Mestrado em Segurança Informática apresentada à Faculdade de Ciências e Tecnologia<br>O presente trabalho visa a mitigação da problemática associada à incidência de ataques Wormhole em redes operadas pelo protocolo de encaminhamento Routing Protocol for Low-Power and Lossy Networks (RPL). Este tipo de ataque pressupõe, tipicamente, a existência de pelo menos dois nós maliciosos na topologia que mantêm entre si uma ligação privada através da qual partilham pacotes legítimos. Esta prática motiva a que os nós que se encontrem nas imediações dos nós infetados assumam, erradamente, nós distantes como seus vizinhos. Ciente das limitações energéticas e computacionais dos dispositivos Internet of Things (IoT) e dado o seu vasto domínio aplicacional, torna-se importante o desenvolvimento de estratégias que promovam a segurança desta tecnologia. Neste seguimento, foi proposto um Intrusion Detection System (IDS), híbrido, baseado em assinaturas, vocacionado à identificação de ataques Wormhole neste tipo de ambiente. A estratégia de deteção desenvolvida passa pelo relacionamento da distância percorrida pelos pacotes, entre os nós remetente e destinatário, com a distância tida como referência para esse trajeto. Dado o seu princípio, o modelo pressupõe a previa determinação da distância entre nós vizinhos, bem como, a inclusão de novos campos nos pacotes em trânsito. A avaliação do sistema de deteção, por recurso a simulação com a ferramenta Cooja, mostrou resultados bastante satisfatórios no que concerne à capacidade de deteção de ataques e identificação de nós maliciosos, apresentando ainda um impacto energético perfeitamente admissível dado o domínio em que se aplica.<br>The present work approaches the problem associated with the incidence of Wormhole attacks in networks operated by the Routing Protocol for Low-Power and Lossy Networks (RPL). This type of attack typically assumes the existence of at least two malicious nodes in the topology that maintain a private connection used to broadcast legitimate packets. This practice motivates nodes that are in the vicinity of the infected nodes to mistakenly assume distant nodes as their neighbours. The energy and computational limitations of Internet of Things (IoT) devices and the vast application domain where they are used, motivate the development of strategies that promote the safety of this technology. Following this, a hybrid Intrusion Detection System (IDS), based on signatures, aimed at identifying Wormhole attacks in this type of environment was proposed. The detection strategy involves the relationship of the distance travelled by the packets, between the sender and recipient nodes, with the distance taken as a reference for this path. The operationalization of this model presupposes the prior determination of the distance between neighbouring nodes, and the inclusion of new fields in the packets in transit. The proposed IDS was evaluated using simulation with the Cooja tool and showed very satisfactory results in terms of the ability to detect attacks and identify malicious nodes. Regarding the energy impact of the solution, it was perfectly acceptable given the domain in which it applies.

The Internet of Things (IoT) proposes a disruptive communication paradigm that allows smart objects to exchange data among themselves to reach a common goal. IoT application scenarios are multiple and can range from a simple smart home lighting system to fully controlled automated manufacturing chains. In the majority of IoT deployments, things are equipped with small devices that can suffer from severe hardware and energy restrictions that are responsible for performing data processing and wireless communication tasks. Thus, due to their features, communication networks that are used by these devices are generally categorized as Low Power and Lossy Networks (LLNs). The considerable variation in IoT applications represents a critical issue to LLN networks, which should offer support to different requirements as well as keeping reasonable quality-of-service (QoS) levels. Based on this challenge, routing protocols represent a key issue in IoT scenarios deployment. Routing protocols are responsible for creating paths among devices and their interactions. Hence, network performance and features are highly dependent on protocol behavior. Also, based on the adopted protocol, the support for some specific requirements of IoT applications may or may not be provided. Thus, a routing protocol should be projected to attend the needs of the applications considering the limitations of the device that will execute them. Looking to attend the demand of routing protocols for LLNs and, consequently, for IoT networks, the Internet Engineering Task Force (IETF) has designed and standardized the IPv6 Routing Protocol for Low Power and Lossy Networks (RPL). This protocol, although being robust and offering features to fulfill the need of several applications, still presents several faults and weaknesses (mainly related to its high complexity and memory requirement), which limits its adoption in IoT scenarios. An alternative to RPL, the Lightweight On-demand Ad Hoc Distancevector Routing Protocol – Next Generation (LOADng) has emerged as a less complicated routing solution for LLNs. However, the cost of its simplicity is paid for with the absence of adequate support for a critical set of features required for many IoT environments. Thus, based on the challenging open issues related to routing in IoT networks, this thesis aims to study and propose contributions to better attend the network requirements of IoT scenarios. A comprehensive survey, reviewing state-of-the-art routing protocols adopted for IoT, identified the strengths and weaknesses of current solutions available in the literature. Based on the identified limitations, a set of improvements is designed to overcome these issues and enhance IoT network performance. The novel solutions are proposed to include reliable and efficient support to attend the needs of IoT applications, such as mobility, heterogeneity, and different traffic patterns. Moreover, mechanisms to improve the network performance in IoT scenarios, which integrate devices with different communication technologies, are introduced. The studies conducted to assess the performance of the proposed solutions showed the high potential of the proposed solutions. When the approaches presented in this thesis were compared with others available in the literature, they presented very promising results considering the metrics related to the Quality of Service (QoS), network and energy efficiency, and memory usage as well as adding new features to the base protocols. Hence, it is believed that the proposed improvements contribute to the state-of-the-art of routing solutions for IoT networks, increasing the performance and adoption of enhanced protocols.<br>A Internet das Coisas, do inglês Internet of Things (IoT), propõe um paradigma de comunicação disruptivo para possibilitar que dispositivos, que podem ser dotados de comportamentos autónomos ou inteligentes, troquem dados entre eles buscando alcançar um objetivo comum. Os cenários de aplicação do IoT são muito variados e podem abranger desde um simples sistema de iluminação para casa até o controle total de uma linha de produção industrial. Na maioria das instalações IoT, as “coisas” são equipadas com um pequeno dispositivo, responsável por realizar as tarefas de comunicação e processamento de dados, que pode sofrer com severas restrições de hardware e energia. Assim, devido às suas características, a rede de comunicação criada por esses dispositivos é geralmente categorizada como uma Low Power and Lossy Network (LLN). A grande variedade de cenários IoT representam uma questão crucial para as LLNs, que devem oferecer suporte aos diferentes requisitos das aplicações, além de manter níveis de qualidade de serviço, do inglês Quality of Service (QoS), adequados. Baseado neste desafio, os protocolos de encaminhamento constituem um aspecto chave na implementação de cenários IoT. Os protocolos de encaminhamento são responsáveis por criar os caminhos entre os dispositivos e permitir suas interações. Assim, o desempenho e as características da rede são altamente dependentes do comportamento destes protocolos. Adicionalmente, com base no protocolo adotado, o suporte a alguns requisitos específicos das aplicações de IoT podem ou não ser fornecidos. Portanto, estes protocolos devem ser projetados para atender as necessidades das aplicações assim como considerando as limitações do hardware no qual serão executados. Procurando atender às necessidades dos protocolos de encaminhamento em LLNs e, consequentemente, das redes IoT, a Internet Engineering Task Force (IETF) desenvolveu e padronizou o IPv6 Routing Protocol for Low Power and Lossy Networks (RPL). O protocolo, embora seja robusto e ofereça recursos para atender às necessidades de diferentes aplicações, apresenta algumas falhas e fraquezas (principalmente relacionadas com a sua alta complexidade e necessidade de memória) que limitam sua adoção em cenários IoT. Em alternativa ao RPL, o Lightweight On-demand Ad hoc Distance-vector Routing Protocol – Next Generation (LOADng) emergiu como uma solução de encaminhamento menos complexa para as LLNs. Contudo, o preço da simplicidade é pago com a falta de suporte adequado para um conjunto de recursos essenciais necessários em muitos ambientes IoT. Assim, inspirado pelas desafiadoras questões ainda em aberto relacionadas com o encaminhamento em redes IoT, esta tese tem como objetivo estudar e propor contribuições para melhor atender os requisitos de rede em cenários IoT. Uma profunda e abrangente revisão do estado da arte sobre os protocolos de encaminhamento adotados em IoT identificou os pontos fortes e limitações das soluções atuais. Com base nas debilidades encontradas, um conjunto de soluções de melhoria é proposto para superar carências existentes e melhorar o desempenho das redes IoT. As novas soluções são propostas para incluir um suporte confiável e eficiente capaz atender às necessidades das aplicações IoT relacionadas com suporte à mobilidade, heterogeneidade dos dispositivos e diferentes padrões de tráfego. Além disso, são introduzidos mecanismos para melhorar o desempenho da rede em cenários IoT que integram dispositivos com diferentes tecnologias de comunicação. Os vários estudos realizados para mensurar o desempenho das soluções propostas mostraram o grande potencial do conjunto de melhorias introduzidas. Quando comparadas com outras abordagens existentes na literatura, as soluções propostas nesta tese demonstraram um aumento do desempenho consistente para métricas relacionadas a qualidade de serviço, uso de memória, eficiência energética e de rede, além de adicionar novas funcionalidades aos protocolos base. Portanto, acredita-se que as melhorias propostas contribuiem para o avanço do estado da arte em soluções de encaminhamento para redes IoT e aumentar a adoção e utilização dos protocolos estudados.

碩士<br>明新科技大學<br>資訊管理研究所<br>101<br>In recent years, the progress of sensing, networking, and communication technologies has stimulated the development of a variety of applications of the Internet of Things (IoT). Smart objects in the IoT are able to form an autonomous network. This kind of network is called the low power and lossy network (LLN), because these smart objects are power-limited, and the quality of links in such networks is likely to be awful. The Routing Over Low power and Lossy networks (ROLL) working group of the Internet Engineering Task Force (IETF) has proposed a IP-based routing protocol for LLNs, called RPL. The RPL depends on the application of interest to determine routing metrics and constraints, and uses them to construct a destination oriented directed acyclic graph, called DODAG. Each node relies on the constructed DODAG to elect the next forwarding node when delivering data packets. This study proposes a novel link quality aware routing protocol, called LQA-RPL, for LLNs to provide an efficient routing. The proposed LQA-RPL, motivated by the traditional RPL, mainly considers the link quality of nodes to construct a proper DODAG to improve the routing performance. To prevent nodes with a low residual energy from becoming forwarding nodes, the proposed LQA-RPL selects the parent with the highest residual energy as a best forwarding node. Simulation results validate that the proposed LQA-RPL reduces energy consumption due to less packet transmissions, compared with the routing protocol running on the DODAG based on the hop count to the destination node. This is because the proposed node rank can reflect the network condition considering the node degree and link quality, and nodes can select the parent with a high residual energy as a forwarding node.

碩士<br>國立臺中教育大學<br>資訊工程學系<br>102<br>Wireless sensor network (WSN) have been the subject of significant research over the recent years. IPv6 over low-power wireless personal area network (6LoWPAN) has been proposing the use of IPv6 solutions in WSN to communicate using Internet protocol (IP). The 6LoWPAN is proposed by IETF which provides IPv6 header compression, fragmentation and reassembly of IPv6 packets over IEEE 802.15.4 networks. In this paper, we present an experimental study on the impact between the packet length of IPv6 in network layer and number of fragments in MAC layer. We conducted our experiments in Contiki test-bed to analysis 6LoWPAN performance with different RSSI and payload size. Experiment results highlight the trade-off between the lengths of IPv6 UDP frame sand link quality for 6LoWPAN performance. Finally, a RSSI-based IPv6 routing metrics for RPL has been proposed based-on our experiment results to enhance the transmission performance in 6LoWPAN.

碩士<br>明新科技大學<br>資訊管理系碩士班<br>106<br>The low power and lossy network (LLN) is composed of many embedded devices with limited capabilities of the operating power, storage space, computing, and communication. A LLN device can communicate with each other via communication technologies (e.g., IEEE 802.15.4, Bluetooth, and low power WiFi). The LLN is characterized by its high packet loss rate, low bandwidth, and unreliable link owing to the usage of wireless technology. The Internet Engineering Task Force has proposed a routing protocol, called RPL for LLNs. Existing studies have also introduced many routing protocols for LLNs, whose main goals include increasing the packet delivery ratio, reducing the transmission latency, and extending the network lifetime. For some LLN applications (e.g., industrial machine-to-machine communication), the frequency of data messages the destination received is more important. Namely, the number of data packets that a destination received during a specific period must exceed a pre-defined threshold. This thesis designs a routing metric, called the path transmission count (PTX), which is determined according to the node’s residual energy, link quality, and pre-defined threshold of reporting frequency. The thesis also proposes a routing protocol using PTX to select the optimal forwarding node to determine the routing path. Simulation results showed that the proposed protocol derived a higher reporting quality, compared with the traditional RPL and the routing scheme considering only the residual energy of LLN nodes. Moreover, the proposed protocol outperforms the traditional RPL and the routing scheme by considering only link quality in terms of network lifetime.

碩士<br>中華大學<br>電機工程學系碩士班<br>102<br>In this thesis, a multiple path routing protocol is proposed to generate a mesh network architecture which is based on a conventional tree network architecture. In addition, a Dijkstra algorithm is adopted to discover the shortest path to construct a virtual mesh network. Another power model method is combined with this multiple path routing protocol to achieve the optimal routing path selection. To evaluate the routing performance of tree and multiple path methods, some performance metrics are used to simulate the performance comparison with the same number of nodes. The performance metrics includes average hop length, network throughput, packet delay, delivery ratio, and packet loss rate. Simulation results show that multiple path routing protocol of a mesh topology achieves better network throughput than a conventional tree topology. However, the mesh topology needs higher link cost to maintain the network links. As a result, combining multiple path routing with power model method to establish a mesh topology and ideally it can reduce 55% energy consumption from traditional methods.