A self-healing framework for WSNs : detection and recovery of faulty sensor nodes and unreliable wireless links

Proponemos un marco conceptual para acoplar técnicas de auto-organización y técnicas de autocuración. A este marco se le llama de auto-curación y es capaz de hacer frente a enlaces inalámbricos inestables y nodos defectuosos. Dividimos el marco en dos componentes principales: la auto-organización y auto-curación. En el componente de auto-organización, nosotros construimos una topología de árbol que determine las rutas hacia el sumidero. En el componente de auto-curación, la topología del árbol se adapta a ambos tipos de fallas siguiendo tres pasos: recopilación de información, detección de fallas, y la recuperación de fallos. En el paso de recopilación de información, los nodos determinan el estado actual de la red mediante la recopilación de información de la capa MAC. En el paso de detección de fallas, los nodos analizan la información recopilada y detectan nodos/enlaces defectuosos. En el paso de recuperación de fallos, los nodos recuperan la topología del árbol mediante la sustitución de componentes defectuosos con redundantes (es decir, componentes de respaldo). Este marco permite una red con resiliencia que se recupera sin agotar los recursos de la red.We propose a conceptual framework for putting together self-organizing and self-healing techniques. This framework is called the self-healing framework and it is capable of coping with unstable wireless links and faulty nodes. We divide the framework into two major components: selforganization and self-healing. In the self-organization component, we build a tree topology that determines routing paths towards the sink. In the self-healing component, the tree topology copes with both types of failures by following three steps: information collection, fault detection, and fault recovery. In the information collection step, the nodes determine the current status of the network by gathering information from the MAC layer. In the fault detection step, the nodes analyze the collected information and detect faulty nodes/links. In the fault recovery step, the nodes recover the tree topology by replacing the faulty components with redundant ones (i.e., backup components). This framework allows a resilient network that recovers itself without depleting the network resources.Doctor en IngenieríaDoctorad

Software Defined Networks based Smart Grid Communication: A Comprehensive Survey

The current power grid is no longer a feasible solution due to ever-increasing user demand of electricity, old infrastructure, and reliability issues and thus require transformation to a better grid a.k.a., smart grid (SG). The key features that distinguish SG from the conventional electrical power grid are its capability to perform two-way communication, demand side management, and real time pricing. Despite all these advantages that SG will bring, there are certain issues which are specific to SG communication system. For instance, network management of current SG systems is complex, time consuming, and done manually. Moreover, SG communication (SGC) system is built on different vendor specific devices and protocols. Therefore, the current SG systems are not protocol independent, thus leading to interoperability issue. Software defined network (SDN) has been proposed to monitor and manage the communication networks globally. This article serves as a comprehensive survey on SDN-based SGC. In this article, we first discuss taxonomy of advantages of SDNbased SGC.We then discuss SDN-based SGC architectures, along with case studies. Our article provides an in-depth discussion on routing schemes for SDN-based SGC. We also provide detailed survey of security and privacy schemes applied to SDN-based SGC. We furthermore present challenges, open issues, and future research directions related to SDN-based SGC.Comment: Accepte

Multichannel Cross-Layer Routing for Sensor Networks

Wireless Sensor Networks are ad-hoc networks that consist of sensor nodes that typically use low-power radios to connect to the Internet. The channels used by the low-power radio often suffer from interference from the other devices sharing the same frequency. By using multichannel communication in wireless networks, the effects of interference can be mitigated to enable the network to operate reliably. This thesis investigates an energy efficient multichannel protocol in Wireless Sensor Networks. It presents a new decentralised multichannel tree-building protocol with a centralised controller for ad-hoc sensor networks. The proposed protocol alleviates the effect of interference, which results in improved network efficiency, stability, and link reliability. The protocol detects the channels that suffer interference in real-time and switches the sensor nodes from those channels. It takes into account all available channels and aims to use the spectrum efficiently by transmitting on several channels. In addition to the use of multiple channels, the protocol reconstructs the topology based on the sensor nodes’ residual energy, which can prolong the network lifetime. The sensor nodes’ energy consumption is reduced because of the multichannel protocol. By using the lifetime energy spanning tree algorithm proposed in this thesis, energy consumption can be further improved by balancing the energy load in the network. This solution enables sensor nodes with less residual energy to remain functional in the network. The benefits of the proposed protocol are described in an extensive performance evaluation of different scenarios in this thesis

Opportunistic data collection and routing in segmented wireless sensor networks

La surveillance régulière des opérations dans les aires de manoeuvre (voies de circulation et pistes) et aires de stationnement d'un aéroport est une tâche cruciale pour son fonctionnement. Les stratégies utilisées à cette fin visent à permettre la mesure des variables environnementales, l'identification des débris (FOD) et l'enregistrement des statistiques d'utilisation de diverses sections de la surface. Selon un groupe de gestionnaires et contrôleurs d'aéroport interrogés, cette surveillance est un privilège des grands aéroports en raison des coûts élevés d'acquisition, d'installation et de maintenance des technologies existantes. Les moyens et petits aéroports se limitent généralement à la surveillance de quelques variables environnementales et des FOD effectuée visuellement par l'homme. Cette dernière activité impose l'arrêt du fonctionnement des pistes pendant l'inspection. Dans cette thèse, nous proposons une solution alternative basée sur les réseaux de capteurs sans fil (WSN) qui, contrairement aux autres méthodes, combinent les propriétés de faible coût d'installation et maintenance, de déploiement rapide, d'évolutivité tout en permettant d'effectuer des mesures sans interférer avec le fonctionnement de l'aéroport. En raison de la superficie d'un aéroport et de la difficulté de placer des capteurs sur des zones de transit, le WSN se composerait d'une collection de sous-réseaux isolés les uns des autres et du puits. Pour gérer cette segmentation, notre proposition s'appuie sur l'utilisation opportuniste des véhicules circulants dans l'aéroport considérés alors comme un type spécial de nœud appelé Mobile Ubiquitous LAN Extension (MULE) chargé de collecter les données des sous-réseaux le long de son trajet et de les transférer vers le puits. L'une des exigences pour le déploiement d'un nouveau système dans un aéroport est qu'il cause peu ou pas d'interruption des opérations régulières. C'est pourquoi l'utilisation d'une approche opportuniste basé sur des MULE est privilégiée dans cette thèse. Par opportuniste, nous nous référons au fait que le rôle de MULE est joué par certains des véhicules déjà existants dans un aéroport et effectuant leurs déplacements normaux. Et certains nœuds des sous- réseaux exploiteront tout moment de contact avec eux pour leur transmettre les données à transférer ensuite au puits. Une caractéristique des MULEs dans notre application est qu'elles ont des trajectoires structurées (suivant les voies de circulation dans l'aéroport), en ayant éventuellement un contact avec l'ensemble des nœuds situés le long de leur trajet (appelés sous-puits). Ceci implique la nécessité de définir une stratégie de routage dans chaque sous-réseau, capable d'acheminer les données collectées des nœuds vers les sous-puits et de répartir les paquets de données entre eux afin que le temps en contact avec la MULE soit utilisé le plus efficacement possible. Dans cette thèse, nous proposons un protocole de routage remplissant ces fonctions. Le protocole proposé est nommé ACME (ACO-based routing protocol for MULE-assisted WSNs). Il est basé sur la technique d'Optimisation par Colonies de Fourmis. ACME permet d'assigner des nœuds à des sous-puits puis de définir les chemins entre eux, en tenant compte de la minimisation de la somme des longueurs de ces chemins, de l'équilibrage de la quantité de paquets stockés par les sous-puits et du nombre total de retransmissions. Le problème est défini comme une tâche d'optimisation multi-objectif qui est résolue de manière distribuée sur la base des actions des nœuds dans un schéma collaboratif. Nous avons développé un environnement de simulation et effectué des campagnes de calculs dans OMNeT++ qui montrent les avantages de notre protocole en termes de performances et sa capacité à s'adapter à une grande variété de topologies de réseaux.The regular monitoring of operations in both movement areas (taxiways and runways) and non-movement areas (aprons and aircraft parking spots) of an airport, is a critical task for its functioning. The set of strategies used for this purpose include the measurement of environmental variables, the identification of foreign object debris (FOD), and the record of statistics of usage for diverse sections of the surface. According to a group of airport managers and controllers interviewed by us, the wide monitoring of most of these variables is a privilege of big airports due to the high acquisition, installation and maintenance costs of most common technologies. Due to this limitation, smaller airports often limit themselves to the monitoring of environmental variables at some few spatial points and the tracking of FOD performed by humans. This last activity requires stopping the functioning of the runways while the inspection is conducted. In this thesis, we propose an alternative solution based on Wireless Sensor Network (WSN) which, unlike the other methods/technologies, combines the desirable properties of low installation and maintenance cost, scalability and ability to perform measurements without interfering with the regular functioning of the airport. Due to the large extension of an airport and the difficulty of placing sensors over transit areas, the WSN might result segmented into a collection of subnetworks isolated from each other and from the sink. To overcome this problem, our proposal relies on a special type of node called Mobile Ubiquitous LAN Extension (MULE), able to move over the airport surface, gather data from the subnetworks along its way and eventually transfer it to the sink. One of the main demands for the deployment of any new system in an airport is that it must have little or no interference with the regular operations. This is why the use of an opportunistic approach for the transfer of data from the subnetworks to the MULE is favored in this thesis. By opportunistic we mean that the role of MULE will be played by some of the typical vehicles already existing in an airport doing their normal displacements, and the subnetworks will exploit any moment of contact with them to forward data to the sink. A particular characteristic of the MULEs in our application is that they move along predefined structured trajectories (given by the layout of the airport), having eventual contact with the set of nodes located by the side of the road (so-called subsinks). This implies the need for a data routing strategy to be used within each subnetwork, able to lead the collected data from the sensor nodes to the subsinks and distribute the data packets among them so that the time in contact with the MULE is used as efficiently as possible. In this thesis, we propose a routing protocol which undertakes this task. Our proposed protocol is named ACME, standing for ACO-based routing protocol for MULE-assisted WSNs. It is founded on the well known Ant Colony Optimization (ACO) technique. The main advantage of ACO is its natural fit to the decentralized nature of WSN, which allows it to perform distributed optimizations (based on local interactions) leading to remarkable overall network performance. ACME is able to assign sensor nodes to subsinks and generate the corresponding multi-hop paths while accounting for the minimization of the total path length, the total subsink imbalance and the total number of retransmissions. The problem is defined as a multi-objective optimization task which is resolved in a distributed manner based on actions of the sensor nodes acting in a collaborative scheme. We conduct a set of computational experiments in the discrete event simulator OMNeT++ which shows the advantages of our protocol in terms of performance and its ability to adapt to a variety of network topologie

Secure-Rpl: Approach To Prevent Resource-Based Attacks In Wireless Sensor Networks Using Balanced Clustering

Internet of Things (IoT) is an evolving computing technology that enables an interconnection amongst physical devices, which offers many advantages, such as easy access to information, cost effectiveness, automation, efficient resource utilisation, reduced human effort and high productivity, all of which have attracted many industry players and researchers. However, the involvement of a vast number of devices and IoT users introduces many issues, including those related to quality of service and security. In IoT, routing amongst resource-constrained devices and nodes is realised by using the routing protocol for a low-power and lossy network (RPL), which selects an optimal route according to the specific objective function

Optimal Design Strategies for Survivable Carrier Ethernet Networks

Ethernet technologies have evolved through enormous standardization efforts over the past two decades to achieve carrier-grade functionalities, leading to carrier Ethernet. Carrier Ethernet is expected to dominate next generation backbone networks due to its low-cost and simplicity. Ethernet's ability to provide carrier-grade Layer-2 protection switching with SONET/SDH-like fast restoration time is achieved by a new protection switching protocol, Ethernet Ring Protection (ERP). In this thesis, we address two important design aspects of carrier Ethernet networks, namely, survivable design of ERP-based Ethernet transport networks together with energy efficient network design. For the former, we address the problem of optimal resource allocation while designing logical ERP for deployment and model the combinatorially complex problem of joint Ring Protection Link (RPL) placements and ring hierarchies selection as an optimization problem. We develop several Mixed Integer Linear Programming (MILP) model to solve the problem optimally considering both single link failure and concurrent dual link failure scenarios. We also present a traffic engineering based ERP design approach and develop corresponding MILP design models for configuring either single or multiple logical ERP instances over one underlying physical ring. For the latter, we propose two novel architectures of energy efficient Ethernet switches using passive optical correlators for optical bypassing as well as using energy efficient Ethernet (EEE) ports for traffic aggregation and forwarding. We develop an optimal frame scheduling model for EEE ports to ensure minimal energy consumption by using packet coalescing and efficient scheduling

On Design, Evaluation and Enhancement of IP-Based Routing Solutions for Low Power and Lossy Networks

In early 2008, a new IETF Working Group (WG), namely ROLL, was chartered to investigate the suitability of existing IP routing protocols for Low Power Lossy Networks (LLNs), which at the time were suffering compatibility issues due to the pervasive use of proprietary protocols. Given the vision of the Internet of Things (IoT) and the role LLNs would play in the future Internet, the IETF set out to standardize an IPv6 based routing solution for such networks. After surveying existing protocols and determining their unsuitability, the WG started designing a new distance vector protocol called RPL (recently standardized in IETF RFC 6550) to fulfill their charter. Joining the WG efforts, we developed a very detailed RPL simulator and using link and traffic traces for existing networks, contributed with a performance study of the protocol with respect to several metrics of interest, such as path quality, end-to-end delay, control plane overhead, ability to cope with instability, etc. This work was standardized as IETF Informational RFC 6687.This detailed study uncovered performance issues for networks of very large scale. In this thesis, we provide an overview of RPL, summarize our findings from the performance study, analysis and comparison with a reactive lightweight protocol and suggest modifications to the protocol that yield significant performance improvements with respect to control overhead and memory consumption in very large scale networks. For future work, we propose a routing technique, named Hybrid Intelligent Path Computation (HIPC), along with modifications to the original RPL protocol standard, that outperforms solely distributed or centralized routing techniques. Finally, we also show how one can facilitate Quality of Service (QoS), load balancing and traffic engineering provision in the IoT without incurring any extra control overhead in number of packets other than that already consumed by the proposed IETF standard, using a combination of centralized and distributed computation.Ph.D., Computer Science -- Drexel University, 201

Position-relative identities in the internet of things: An evolutionary GHT approach

The Internet of Things (IoT) will result in the deployment of many billions of wireless embedded systems creating interactive pervasive environments. It is envisaged that devices will cooperate to provide greater system knowledge than the sum of its parts. In an emergency situation, the flow of data across the IoT may be disrupted, giving rise to a requirement for machine-to-machine interaction within the remaining ubiquitous environment. Geographic hash tables (GHTs) provide an efficient mechanism to support fault-tolerant rendezvous communication between devices. However, current approaches either rely on devices being equipped with a GPS or being manually assigned an identity. This is unrealistic when the majority of these systems will be located inside buildings and will be too numerous to expect manual configuration. Additionally, when using GHT as a distributed data store, imbalance in the topology can lead to storage and routing overhead. This causes unfair work load, exhausting limited power supplies as well as causing poor data redundancy. To deal with these issues, we propose an approach that balances graph-based layout identity assignment, through the application of multifitness genetic algorithms. Our experiments show through simulation that our multifitness evolution technique improves on the initial graph-based layout, providing devices with improved balance and reachability metrics