Vers une structuration auto-stabilisante des réseaux Ad Hoc

International audienceIn this paper, we present a self-stabilizing asynchronous distributed clustering algorithm that builds non-overlapping k-hops clusters. Our approach does not require any initialization. It is based only on information from neighboring nodes with periodic messages exchange. Starting from an arbitrary configuration, the network converges to a stable state after a finite number of steps. Firstly, we prove that the stabilization is reached after at most n+2 transitions and requires (u+1)* log(2n+k+3) bits per node, whereΔu represents node's degree, n is the number of network nodes and k represents the maximum hops number. Secondly, using OMNet++ simulator, we performed an evaluation of our proposed algorithm.Dans cet article, nous proposons un algorithme de structuration auto-stabilisant, distribuéet asynchrone qui construit des clusters de diamètre au plus 2k. Notre approche ne nécessite aucuneinitialisation. Elle se fonde uniquement sur l’information provenant des noeuds voisins à l’aided’échanges de messages. Partant d’une configuration quelconque, le réseau converge vers un étatstable après un nombre fini d’étapes. Nous montrons par preuve formelle que pour un réseau de nnoeuds, la stabilisation est atteinte en au plus n + 2 transitions. De plus, l’algorithme nécessite uneoccupation mémoire de (u + 1) log(2n + k + 3) bits pour chaque noeud u où u représente ledegré (nombre de voisins) de u et k la distance maximale dans les clusters. Afin de consolider lesrésultats théoriques obtenus, nous avons effectué une campagne de simulation sous OMNeT++ pourévaluer la performance de notre solution

Vers une gestion adaptative des réseaux complexes (cas de la surveillance décentralisée de données agrégées)

Les infrastructures de gestion autonomes basées sur des fonctions self-* offrent un premier degré d'autonomie mais restent souvent fondées sur des approches non-adaptatives. Cependant, leurs réseaux cibles sont dynamiques en termes, par exemple, de taille, mobilité, services et usages. Adapter ces infrastructures au contexte opérationnel des réseaux qui les supportent est donc essentiel pour garantir leur performance et minimiser leur coût. Le travail mené dans cette thèse vise à concevoir une infrastructure de gestion autonome capable de s'auto-adapter au contexte opérationnel du réseau qu'elle contrôle. La fonction de gestion à laquelle nous nous intéressons est la surveillance décentralisée d'informations agrégées, qui peut être basée sur des protocoles épidémiques, à base d arbres ou de vue située. Pour ce faire, nous proposons une approche auto-adaptative et décentralisée, basée entre autres sur l'inférence floue et sur la prise de décision multicritère. Pour cela, nous avons étudié les protocoles d'agrégation existants, puis nous avons comparé un protocole représentatif de chaque catégorie. En se fondant sur ces résultats, l'approche proposée analyse continuellement l'état du réseau afin de déduire les propriétés du contexte courant et choisit la stratégie d'agrégation adéquate en fonction de celui-ci. Ainsi, la stratégie sélectionnée est celle qui maximise la performance de l'agrégation et minimise son coût. La validation multicritère par simulation de l approche proposée montre que celle-ci fournit une bonne performance avec un coût acceptableAutonomous management infrastructures based on self-* functions currently offer a first degree of autonomy, but they are often based on non-adaptive approaches. Conversely, their target networks are dynamics in terms of, for example, size, mobility, services and usages. Thus, adapting self-management infrastructures to the supporting network operational behavior is essential in order to ensure their performance and minimize their cost. The work carried out in this thesis aims at de-signing an autonomous management infra-structure able to adapt itself to the operational context of the managed network. The management function we are interested in is the decentralized monitoring of aggregated information, which can be based on gossip, aggregation trees or situated view protocols. To achieve these objectives, we propose a de-centralized self-adaptive management frame-work, based on fuzzy inference and multiple criteria decision making. For this purpose, we surveyed the existing decentralized aggregation protocols, and then we benchmarked one typical protocol from each category. Based on the obtained results, the proposed approach continuously analyzes the network state in order to retrieve the properties of the current context, and then selects the best aggregation strategy to use accordingly. Thus, the selected strategy is the one that maximizes the performance of the aggregation and minimizes its cost. The multiple criteria validation of the pro-posed approach through simulation shows that this one provides a good performance with an acceptable costTROYES-SCD-UTT (103872102) / SudocSudocFranceF

Simulation and Real-Time Management of Innovative Mutualized Urban Logistics Systems

Si vous jugez que le contenu du résumé est plus proche de la thématique "Logistique, localisation, transport et contrôle aérien", je vous prie de bien vouloir le réaffecter à celle-ci. Un rapport scientifique plus détaillé est disponible sur le lien suivant : http://rafikmak.free.fr/Files/MODUMSreportMAK.pdfInternational audienceThis work is done in the context of the MODUM (Mutualization and Optimization of Urban Freights Distribution) ANR project. The latter aims at proposing a new organization of urban merchandize distribution based on mutualized and optimized resources. For this, shuttles are used to carry goods between a set of urban distribution centers connected by a ring around a city, and more light and ecological vehicles are used to serve customers inside the city. In this context, our contribution is twofold. On one hand, we develop a set of models and mechanisms to manage merchandize distribution and we re-utilize those proposed in the project. We develop a reservation system that enables customers to request a merchandize transportation service (delivery and collect) or to book a vehicle for a self-service. For this, two main decision modules are implemented: (1) an online module that immediately processes arriving requests by searching for a feasible solution and decides to accept or reject them, and (2) an offline module that is executed when the reservation system is closed. It looks for optimized solutions starting from the feasible schedule defined by the online module. On the other hand, we propose and develop a new discrete event simulator MODUMS (MODUM Simulator) which implements such a system and evaluates its economical and environmental impact. MODUMS takes as inputs the two previous decision modules, information about the transportation means, geographic data and demand information with the tuned probability distributions of requests. It gives as outputs indicators on the impact of mutualization on the quality of urban logistics in terms of, for example, rejection rate of self-service requests, satisfying time of delivery/collect requests and CO2 impact. This work opens challenging algorithmic and modeling issues like in the management of the ring and the design of decision modules. A research report is available at: http://rafikmak.free.fr/Files/MODUMSreportMAK.pdf</p

Situated vs. Global Aggregation Schemes for Autonomous Management Systems

International audienceIn the context of autonomous network management, the Autonomic Managers (AMs) need to collect management information from other elements in order to infer an overall state of the network considered by the decision making process. Two concurrent strategies are commonly used to achieve this operation. On one hand, approaches based on a situated view only gather information in a bounded neighborhood, thus providing a high reactivity to AMs for control operations. On the other hand, approaches based on a global view provide a good accuracy at the cost of a larger convergence time. Being able to choose the best approach in a given context is crucial to ensure the efficiency of an autonomous management system. Thus, in this paper, we perform an exhaustive performance analysis of these approaches by considering typical schemes of both of them, namely a one-hop and two-hops situated view against gossip- and tree-based global aggregation schemes. Metrics we consider are the convergence time, communication and computation cost, scalability and the accuracy of estimated aggregates. Given them, we show under which conditions an approach outperforms the others

Towards a P2P-based deployment of network management information

Abstract. Standard static centralized network management approaches are unsuitable for managing large, dynamic and distributed networks. Some decentralized approaches based on the P2P model have emerged to overcome the limitations of these centralized approaches like lack of scalability and fault-tolerance. However, they do not address issues related to the deployment of management information which is crucial in a decentralized management context because of the heterogeneous nature of this kind of information. Furthermore, current decentralized approaches still faces difficulties to ensure security, persistence and consistency of management information. In this paper, we investigate the use of a DHT as a framework for the deployment of network management information. First, we feature management information from a deployment perspective. Then, we propose a basic deployment strategy. We evaluate this approach in the context of the monitoring service considering network scalability, propagation delay and information loss under churn

Situated vs. Global Aggregation Schemes for Autonomous Management Systems

International audienceIn the context of autonomous network management, the Autonomic Managers (AMs) need to collect management information from other elements in order to infer an overall state of the network considered by the decision making process. Two concurrent strategies are commonly used to achieve this operation. On one hand, approaches based on a situated view only gather information in a bounded neighborhood, thus providing a high reactivity to AMs for control operations. On the other hand, approaches based on a global view provide a good accuracy at the cost of a larger convergence time. Being able to choose the best approach in a given context is crucial to ensure the efficiency of an autonomous management system. Thus, in this paper, we perform an exhaustive performance analysis of these approaches by considering typical schemes of both of them, namely a one-hop and two-hops situated view against gossip- and tree-based global aggregation schemes. Metrics we consider are the convergence time, communication and computation cost, scalability and the accuracy of estimated aggregates. Given them, we show under which conditions an approach outperforms the others

A survey and performance evaluation of decentralized aggregation schemes for autonomic management

International audienc

Une approche adaptative pour la surveillance d'informations agrégées dans les réseaux complexes

National audienceDans le domaine de la gestion autonome, être capable de concevoir des infrastructures efficaces qui opèrent à un coût moindre est une problématique importante. Dans ce contexte, nous proposons une architecture auto-adaptative pour la surveillance de données agrégées. Cette architecture surveille l'état opérationnel du réseau sur lequel elle est déployée et met en œuvre dynamiquement le protocole d'agrégation de données le plus utile en fonction du contexte courant. Pour ce faire, elle repose sur la logique floue et une prise de décision multi-critère. Nous validons cette proposition par simulation, en montrant la précision de nos composants ainsi que la limite du coût induit

Vers un modèle de déploiement décentralisé de l'information de gestion

International audienc

Impact of Dynamics on Situated and Global Aggregation Schemes

Part 5: P2P and Aggregation SchemesInternational audienceRecently, numerous management approaches have emerged in order to manage networks and services in a decentralized and autonomous way. Some of them propose to minimize their cost by using a situated view when collecting aggregates for the decision making process, while others propose to improve their accuracy by using a more conventional approach which is global view. So far, little attention is given to the evaluation of situated view while many studies propose to evaluate global approaches. As a consequence, there is no work in the literature that compares the performance of situated and global aggregation schemes. Being able to choose the suitable approach for a given context is still a real challenge. Mastering it will ensure the e fficiency of the autonomous management system. In this paper, we present a comparative study of situated and global schemes deployed over large scale and dynamic networks. We consider two factors: network and information dynamics. We implement typical aggregation schemes from each category and then we compare them according to the accuracy of the estimated aggregates and the e ciency of the decision making process