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International audience; Low-Power Wide-Area Networks (LPWAN) connect a large number of battery-powered wireless devices over long distances. Among them, Long Range Wide Area Networks (LoRaWAN) implement a Pure ALOHA medium access scheme to save device energy by minimizing the radio usage. However, frame collisions restrain the network scalability when the traffic load increases. In this context, synchronization is used to exploit the available bandwidth more efficiently by controlling the timing of frame transmissions and reducing the collision probability. Remarkably, the network throughput is increased at the cost of an extra energy demand due to the inherent overhead. In that, the entailed network scenario is still supposed to address low power applications. This paper timely presents LoRaSync, an energyefficient synchronization scheme designed for LoRa networks of any size. An accurate clock drift model was established based on measurements made on real cheap devices, and leveraged to support the design of LoRaSync. Our mechanism has been used to evaluate the same ALOHA-based random access but on a timeslotted basis, thus increasing the maximum achievable throughput compared to the legacy access. Throughput and energy efficiency models are established to evaluate the performances of a LoRaSync-operated network. These models are validated with a simulation environment mimicking large-scale deployments, and then used to determine the most energy efficient slot size for any traffic load. As a final proof of concept, LoRaSync has been implemented and tested on a LoRa testbed to demonstrate the feasibility of our solution on real hardware.

International audience; In the 90s, Q-routing assisted by reinforcement learning was introduced by Boyan and Littman with interesting results in terms of quality of service. Some recent works continue to promote the idea through improvement of the algorithm or specialized extensions. In this paper, we propose a simple modification to workaround the greedy behaviour of Q-routing by considering epoch notion. In comparison with the original Q-routing and the standard OLSRv2 under Qualnet simulator, we show that our extension provides an interesting improvement in terms of packet delivery ratio on the original irregular grid of Boyan and Littman with wireless links.

International audience; —We review the research literature investigating systems in which mobile entities can carry data while they move. These entities can be either mobile by nature (e.g., human beings and animals) or mobile by design (e.g., trains, airplanes, and cars). The movements of such entities equipped with storage capabilities create a communication channel which can help overcome the limitations or the lack of conventional data networks. Common limitations include the mismatch between the capacity offered by these networks and the traffic demand or their limited deployment owing to environmental factors. Application scenarios include offloading traffic off legacy networks for capacity improvement, bridging connectivity gaps, or deploying ad hoc networks in challenging environments for coverage enhancement.

Recently, the giants of the Internet are adopting every day more and more the benefits of virtualization within the data center. This technology reduces significantly power consumption, energy consumption, as well as operational cost. Furthermore, not long ago, this promising solution is studied by the research communities to be extended for network virtualization deployment. At this time, the physical networking devices can be virtualized, providing an intelligent abstraction via virtual network software that makes easy to deploy and manage network resources. The search giant Google has deployed SDN to experiment with the inter-connection between their data center around the world.With the exponential growth of devices connected to the Internet, security network is one of the hardest challenge for network managers. In this context, the new networking paradigm, the Software Defined Networking (SDN), introduces many opportunities and provides the potential to overcome those challenges. In our approach, we first propose a new SDN based architecture for networking with or without infrastructure, that we call an SDN domain. This domain includes wired network, wireless network and Ad-Hoc networks. Next, a second architecture includes sensor networks in an SDN-based network and in a domain. Third, interconnecting multiple domains and we describe how we can enhance the security of each domain and how to distribute the security rules in order not to compromise the security of one domain. Finally, we present a new secure and distributed architecture for ad-hoc networks and IoT (Internet of Things).; Les acteurs majeurs d'Internet ont mis en place dans leurs datacenters de plus en plus de virtualisation pour permettre de faire fonctionner plusieurs systèmes d'exploitation simultanément sur un même serveur physique. Cette technologie a permis de faire des économies énergétiques et financières importantes. Elle utilise également au niveau de la recherche depuis peu de temps, en particulier dans le domaine des réseaux. Traditionnellement, ce sont des équipements physiques tels que des commutateurs ou des routeurs qui se chargent du transfert de l'information, à la suite d'une programmation effectuée par les administrateurs. Dorénavant, ces équipements sont également virtualisés et la décision prise pour l'acheminement de l'information se fait de manière logiciel. Des expérimentations de cette technologie de virtualisation du réseau, aussi appelé Software-Defined Network (SDN), ont été mise en place par Google pour relier ses principaux datacenters [1], au travers le monde.Dans le cadre de ce projet, nous présentons une nouvelle architecture basée sur les concepts du SDN, pour les réseaux avec ou sans infrastructure. Cette architecture est composée de réseaux filaires, sans fil et ad-hoc. Elle est ensuite proposée pour intégrer des objets communicants dans un domaine du réseau SDN. Différents domaines sont alors interconnectés pour que la gestion du réseau soit distribuée, sans toutefois réduire le niveau de sécurité. Cette étude propose une nouvelle architecture sécurisée et distribuée pour l'IoT (Internet des Objets).

Recently, the giants of the Internet are adopting every day more and more the benefits of virtualization within the data center. This technology reduces significantly power consumption, energy consumption, as well as operational cost. Furthermore, not long ago, this promising solution is studied by the research communities to be extended for network virtualization deployment. At this time, the physical networking devices can be virtualized, providing an intelligent abstraction via virtual network software that makes easy to deploy and manage network resources. The search giant Google has deployed SDN to experiment with the inter-connection between their data center around the world.With the exponential growth of devices connected to the Internet, security network is one of the hardest challenge for network managers. In this context, the new networking paradigm, the Software Defined Networking (SDN), introduces many opportunities and provides the potential to overcome those challenges. In our approach, we first propose a new SDN based architecture for networking with or without infrastructure, that we call an SDN domain. This domain includes wired network, wireless network and Ad-Hoc networks. Next, a second architecture includes sensor networks in an SDN-based network and in a domain. Third, interconnecting multiple domains and we describe how we can enhance the security of each domain and how to distribute the security rules in order not to compromise the security of one domain. Finally, we present a new secure and distributed architecture for ad-hoc networks and IoT (Internet of Things)., Les acteurs majeurs d'Internet ont mis en place dans leurs datacenters de plus en plus de virtualisation pour permettre de faire fonctionner plusieurs systèmes d'exploitation simultanément sur un même serveur physique. Cette technologie a permis de faire des économies énergétiques et financières importantes. Elle utilise également au niveau de la recherche depuis peu de temps, en particulier dans le domaine des réseaux. Traditionnellement, ce sont des équipements physiques tels que des commutateurs ou des routeurs qui se chargent du transfert de l'information, à la suite d'une programmation effectuée par les administrateurs. Dorénavant, ces équipements sont également virtualisés et la décision prise pour l'acheminement de l'information se fait de manière logiciel. Des expérimentations de cette technologie de virtualisation du réseau, aussi appelé Software-Defined Network (SDN), ont été mise en place par Google pour relier ses principaux datacenters [1], au travers le monde.Dans le cadre de ce projet, nous présentons une nouvelle architecture basée sur les concepts du SDN, pour les réseaux avec ou sans infrastructure. Cette architecture est composée de réseaux filaires, sans fil et ad-hoc. Elle est ensuite proposée pour intégrer des objets communicants dans un domaine du réseau SDN. Différents domaines sont alors interconnectés pour que la gestion du réseau soit distribuée, sans toutefois réduire le niveau de sécurité. Cette étude propose une nouvelle architecture sécurisée et distribuée pour l'IoT (Internet des Objets).

International audience; Unmanned Aerial Vehicles (UAVs) can be a solution for deploying temporary networks by serving as Access Points to users on the ground. The aim is to provide multiple communication services (voice, data, video, etc.) over a specific area. The network must be deployed quickly for a relatively short period (emergency situations, sporting events, etc.), in the case of cellular network overload or blackout. A Flying Ad-Hoc Network will be deployed to cover all the potential users. The objective of this paper is to investigate the impact of drone replacement due to the limitation of battery lifetime. A constraint for this kind of network is service continuity. For this purpose, an adaptation for the routing mechanism is proposed, to overcome the loss of connectivity observed in the simulations. In the beginning, a state of the art on use cases employing drones is given, followed by a description of our scenario. Thenceforth, the system is described as well as the deployment mechanism and the induced connectivity loss. In the end, we present a way to adapt the routing scheme so that the network remains connected when a node is replaced due to energy level reasons.

International audience; We address the problem of collecting data in a wireless sensor network, where network coding is used for data transmission. The temporal correlation between the measure- ments is exploited to recover the data at the receiver. For this purpose, network encoding operations are considered in conjunction with lossy source compression, performed by an LDGM code set generated during transmission. The decoding is carried out using the iterative doping algorithm based on the sum product algorithm, on a graph which represents the LDGM encoding equations. Consequently, we first study the design tradeoffs of LDGM-based lossy source coding for significant parameters, such as packet size reduction and distorsion. In addition, we aim to show the prospective impact of the network coding on a wireless sensors network. This involves identifying how linear codes improve key performance criteria for networks such as rate, delay, and convergence time. Our work was applied to a real case study to highlight consistency and efficiency of our proposed system

International audience; With the rapid advancement in the automotive industry, vehicles are now coming with equipped sensors, on board units and other processing as well communication capabilities. VANET have come into existence because of this advancement and has offered various research dimensions to the industry. VANET considered as a distinct type of Mobile Ad Hoc Networks, holds the opportunity to make people's life and death decisions by predicting and helping the drivers and other people about the road safety and other critical conditions. This paper outlines the VANET definition, its architecture and protocols from a research point of view. Although, VANET are a subset of MANET but they are also the future of Intelligent Transport Systems. Such varied applications areas of VANET and future research directions of VANET are provided in the end of paper.

—With the exponential growth of devices connected to the Internet, security networks as one of the hardest challenge for network managers. Maintaining and securing such large scale and heterogeneous network is a challenging task. In this context, the new networking paradigm, the Software Defined Networking (SDN), introduces many opportunities and provides the potential to overcome those challenges. In this article, we first present a new SDN based architecture for networking with or without infrastructure, that we call an SDN domain. A single domain includes wired network, wireless network and Ad-Hoc networks. Next, we propose a second architecture to include sensor networks in an SDN-based network and in a domain. Third, we interconnect multiple domains and we describe how we can enhanced the security of each domain and how to distribute the security rules in order not to compromise the security of one domain. Finally, we propose a new secure and distributed architecture for IoT (Internet of Things). —With the exponential growth of devices connected to the Internet, security networks as one of the hardest challenge for network managers. Maintaining and securing such large scale and heterogeneous network is a challenging task. In this context, the new networking paradigm, the Software Defined Networking (SDN), introduces many opportunities and provides the potential to overcome those challenges. In this article, we first present a new SDN based architecture for networking with or without infrastructure, that we call an SDN domain. A single domain includes wired network, wireless network and Ad-Hoc networks. Next, we propose a second architecture to include sensor networks in an SDN-based network and in a domain. Third, we interconnect multiple domains and we describe how we can enhanced the security of each domain and how to distribute the security rules in order not to compromise the security of one domain. Finally, we propose a new secure and distributed architecture for IoT (Internet of Things).

The Optimized Link State Routing Protocol version 2 (OLSRv2) includes the ability to assign metrics to links and to use those metrics to allow routing by other than minimum hop count routes. This document provides a historic record of the rationale for, and design considerations behind, how link metrics were included in OLSRv2. Status of This Memo This document is not an Internet Standards Track specification; it is published for informational purposes. This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Not all documents approved by the IESG are a candidate for any level of Internet Standard; see Section 2 of RFC 5741. Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc7185.

This document revises, extends, and replaces RFC 6622. It describes general and flexible TLVs for representing cryptographic Integrity Check Values (ICVs) and timestamps, using the generalized Mobile Ad Hoc Network (MANET) packet/message format defined in RFC 5444. It defines two Packet TLVs, two Message TLVs, and two Address Block TLVs for affixing ICVs and timestamps to a packet, a message, and one or more addresses, respectively. Status of This Memo This is an Internet Standards Track document. This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 5741.

This specification describes version 2 of the Optimized Link State Routing Protocol (OLSRv2) for Mobile Ad Hoc Networks (MANETs). Status of This Memo This is an Internet Standards Track document. This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 5741. Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc7181.

International audience; In this paper, the problem of channel selection and power control is jointly analyzed in the context of multiple-channel clustered ad-hoc networks, i.e., decentralized networks in which radio devices are arranged into groups (clusters) and each cluster is managed by a central controller (CC). This problem is modeled by game in normal form in which the corresponding utility functions are designed for making some of the Nash equilibria (NE) to coincide with the solutions to a global network optimization problem. In order to ensure that the network operates in the equilibria that are globally optimal, a learning algorithm based on the paradigm of trial and error learning is proposed. These results are presented in the most general form and therefore, they can also be seen as a framework for designing both games and learning algorithms with which decentralized networks can operate at global optimal points using only their available local knowledge. The pertinence of the game design and the learning algorithm are highlighted using specific scenarios in decentralized clustered ad hoc networks. Numerical results confirm the relevance of using appropriate utility functions and trial and error learning for enhancing the performance of decentralized networks.

International audience; This book constitutes the joint refereed proceedings of the 5th International Workshop on Communication Technologies for Vehicles/Trains, Nets4Cars 2013 and Nets4Trains 2013, held in Vilnius, Lithuania, in May 2013. The 12 full papers of the road track and 5 full papers of the rail track presented together with 3 invited talks were carefully reviewed and selected from 24 submissions. They address topics such as intra-vehicle, inter-vehicle and vehicle to infrastructure communications (protocols and standards), mobility and traffic models (models, methodologies, and techniques), testing, and applications.

International audience; This contribution is about emergency networks and how to counter partitioning occurring in a mobile ad hoc network. Our approach is based on clustering where a distributed election process is run in order to iden- tify a node called clusterhead that will provide interconnection services with the rest of the network. While the election process is based on a pub- lished protocol called KCMBC, this contribution focuses on an aspect not covered by KCMBC, which is cluster maintenance. Cluster maintenance makes sure that the election process stays valid even though the partition topology changes: nodes join and leave the cluster. In this context, we propose and evaluate a maintenance protocol called passive maintenance that generates few control messages while maintaining cluster integrity. Because our solution is assessed by means of simulation, it is important to set a representative framework for evaluation. For this reason, the contri- bution starts with a discussion on network topology modeling. Different models that are used for representing forest firefighting are compared, considering simplicity and representativity.

International audience; Dealing with large, critical mobile systems and infrastructures where ongoing changes and resilience are paramount leads to very complex and difficult challenges for system evaluation. These challenges call for approaches that are able to integrate several evaluation methods for the quantitative assessment of QoS indicators which have been applied so far only to a limited extent. In this paper, we propose the holistic evaluation framework developed during the recently concluded FP6-HIDENETS project. It is based on abstraction and decomposition, and it exploits the interactions among different evaluation techniques including analytical, simulative, and experimental measurement approaches, to manage system complexity. The feasibility of the holistic approach for the analysis of a complete end-to-end scenario is first illustrated presenting two examples where mobility simulation is used in combination with stochastic analytical modeling, and then through the development and implementation of an evaluation workflow integrating several tools and model transformation steps.

International audience; A common operation in wireless ad hoc networks is the flooding of broadcast messages to establish network topologies and routing tables. The flooding of broadcast messages is, however, a resource consuming process. It might require the retransmission of messages by most network nodes. It is, therefore, very important to optimize this operation. In this paper, we first analyze the multipoint relaying (MPR) flooding mechanism used by the Optimized Link State Routing (OLSR) protocol to distribute topology control (TC) messages among all the system nodes. We then propose a new flooding method, based on the fusion of two key concepts: distance-enabled multipoint relaying and connected dominating set (CDS) flooding. We present experimental simulations that show our approach improves the performance of previous existing proposals.

International audience; The core of the Optimized Link State Routing (OLSR) protocol is the selection of Multipoint Relays (MPRs) as a flooding mechanism for distributing control traffic messages. A node in an OLSR network, selects its MPR set such that all two-hop neighbors are reachable through, at least, one MPR. However, if an MPR misbehaves during the execution of the protocol, the connectivity of the network is compromised. Additional coverage in the selection of the MPRs helps to mitigate the effect of control traffic attacks. RFC3626 defines the selection of MPRs with additional coverage. Nevertheless, the overhead of the network increases due to the added number of control traffic messages. In this paper, we propose an improved MPR selection with additional coverage. Every node selects, if it is possible, k + 1 disjoint MPR sets. The union of those sets, is a k-robust-MPR set. Thus, given a node, alternative paths are created to reach any destination two-hops away. We test both approaches against two kinds of adversaries misbehaving during the execution of the protocol. Our proposed MPR selection with additional coverage mitigates the effect of control traffic attacks by offering equivalent protection compared to the MPR selection with extra coverage presented in RFC3626, but reducing the overhead generated by redundant control information.

International audience; This paper addresses the dependability modelling and evaluation of two safety-related applications that are based on communications between vehicles and between vehicles and fixed infrastructures: automated highway systems and virtual black boxes. The main objective is to develop model-based evaluation approaches to analyze and quantify the dependability of such applications. Modelling is based on Stochastic Activity Networks. The results show the significant impact of some mobility parameters on application availability and safety.

International audience; This book constitutes the thoroughly refereed post-conference proceedings of the two international workshops DPM 2009, the 4th International Workshop on Data Privacy Management, and SETOP 2009, the Second International Workshop on Autonomous and Spontaneous Security, collocated with the ESORICS 2009 symposium in St. Malo, France, in September 2009. The 8 revised full papers for DPM 2009, selected from 23 submissions, presented together with two keynote lectures are accompanied by 9 revised full papers of SETOP 2009; all papers were carefully reviewed and selected for inclusion in the book. The DPM 2009 papers cover topics such as privacy in service oriented architectures, privacy-preserving mechanisms, crossmatching and indistinguishability techniques, privacy policies, and disclosure of information. The SETOP 2009 papers address all current issues within the sope of security policies, identification and privacy, as well as security mechanisms.

International audience; Hybrid networks are formed by a combination of access points and mobile nodes such that the mobile nodes can communicate both through the access points and using ad-hoc networking among themselves. This work deals with providing efficient routing between mobile devices in hybrid networks. Specifically, we assume the existence of a spanning tree from each access point to all mobile devices within the transitive transmission range of the access point. We utilize this spanning tree to design a family of efficient point-to-point routing protocols for communication between the mobile devices themselves. The protocols utilize the tree structure in order to avoid expensive flooding of the entire network. The paper includes a detailed simulation study of several representative communication patterns, which compares our approaches to DSR.

International audience; Wireless sensor networks with multiple users collecting data directly from the sensors have many potential applications. An important problem is to allocate for each user a query range to achieve certain global optimality while avoid congesting the sensors in the meanwhile. We study this problem for a ZigBee cluster tree by formulating it into a multi-dimensional multi-choice knapsack problem. Maximum overall query range and max-min fair query range objectives are investigated. Distributed algorithms are proposed which exploit the ZigBee cluster tree structure to keep the computation local. Extensive simulations show that the proposed methods achieve good approximation to the optimal solution with little overhead and improve the network performance.

International audience; While fault monitoring is a well-known issue in fixed wired networks, ad-hoc networks provide new challenges with respect to this issue: in particular, the monitoring task may be hindered at any time by the impossibility to observe a given node. This paper proposes a fault monitoring approach for ad-hoc networks which takes into account this constraint. Our approach is based on an information theory measure suitable to the intermittence of ad-hoc nodes and capable to detect network failures by inference. We define a distributed monitoring scheme with several collaborative detection methods, and we detail a self-configuration mechanism based on the K-means classification algorithm. We show how this solution can be integrated into a management architecture and evaluate its performance based an extensive set of simulations.

Today, wireless network technologies (WLAN/WPAN) available on the market are numerous and complementary. Nevertheless, none of these technologies present some real guaranties on message delivery within a bounded delay. However, this kind of constraint is a recurrent need in the industrial communication application context. To solve this problem, our research work proposes an original full deterministic MAC layer for an IEEE 802.15.4 Low-Power Wireless Personal Area Network.We first present a state of the art on principal wireless network standards and technologies, Quality of Service protocols and commonly used Medium Access Control mechanisms. Then, we present the IEEE 802.15.4/ZigBee wireless technology which is used as a basis for our works. This study has enabled us to identify weakness on 802.15.4 Medium Access Control, in particular for highly time-constrained data transports. Our research works propose to solve these identified weaknesses by proposing an original full deterministic medium access method. Several validation methods/tools were used: Petrinets, simulation and prototyping. Obtained results are then exposed and discussed.; Aujourd'hui, les technologies de réseaux sans fil (WLAN/WPAN) présentes sur le marché sont nombreuses et globalement complémentaires. Cependant, trop peu d'entre elles proposent de réelles garanties sur la remise de messages dans un temps borné alors que ces exigences sont fondamentales dans le cadre d'une utilisation de type industriel. Dans le cadre de nos travaux, nous proposons une nouvelle couche MAC entièrement déterministe pour un réseau sans fil personnel basse consommation (LP-WPAN) IEEE 802.15.4 présentant des garanties sur le plan temporel.Tout d'abord, un état de l'art est effectué sur les principaux réseaux sans fil existants, les mécanismes de gestion de la Qualité de Service et les méthodes d'accès généralement utilisées. Nous présentons ensuite la technologie IEEE 802.15.4/ZigBee sur laquelle sont basés nos travaux. Cette étude approfondie nous a permis d'identifier certaines imperfections au niveau de la méthode d'accès par rapport aux contraintes temporelles. Nous proposons de combler ces lacunes par la création d'une couche MAC entièrement déterministe dont nous présentons les caractéristiques et les nouvelles fonctionnalités. Plusieurs méthodes complémentaires ont été utilisées pour valider nos propositions : Réseaux de Petri, simulation et prototypage réel. Les résultats obtenus et les analyses de ces trois études sont exposés.

Today, wireless network technologies (WLAN/WPAN) available on the market are numerous and complementary. Nevertheless, none of these technologies present some real guaranties on message delivery within a bounded delay. However, this kind of constraint is a recurrent need in the industrial communication application context. To solve this problem, our research work proposes an original full deterministic MAC layer for an IEEE 802.15.4 Low-Power Wireless Personal Area Network.We first present a state of the art on principal wireless network standards and technologies, Quality of Service protocols and commonly used Medium Access Control mechanisms. Then, we present the IEEE 802.15.4/ZigBee wireless technology which is used as a basis for our works. This study has enabled us to identify weakness on 802.15.4 Medium Access Control, in particular for highly time-constrained data transports. Our research works propose to solve these identified weaknesses by proposing an original full deterministic medium access method. Several validation methods/tools were used: Petrinets, simulation and prototyping. Obtained results are then exposed and discussed.; Aujourd'hui, les technologies de réseaux sans fil (WLAN/WPAN) présentes sur le marché sont nombreuses et globalement complémentaires. Cependant, trop peu d'entre elles proposent de réelles garanties sur la remise de messages dans un temps borné alors que ces exigences sont fondamentales dans le cadre d'une utilisation de type industriel. Dans le cadre de nos travaux, nous proposons une nouvelle couche MAC entièrement déterministe pour un réseau sans fil personnel basse consommation (LP-WPAN) IEEE 802.15.4 présentant des garanties sur le plan temporel.Tout d'abord, un état de l'art est effectué sur les principaux réseaux sans fil existants, les mécanismes de gestion de la Qualité de Service et les méthodes d'accès généralement utilisées. Nous présentons ensuite la technologie IEEE 802.15.4/ZigBee sur laquelle sont basés nos travaux. Cette étude approfondie nous a permis d'identifier certaines imperfections au niveau de la méthode d'accès par rapport aux contraintes temporelles. Nous proposons de combler ces lacunes par la création d'une couche MAC entièrement déterministe dont nous présentons les caractéristiques et les nouvelles fonctionnalités. Plusieurs méthodes complémentaires ont été utilisées pour valider nos propositions : Réseaux de Petri, simulation et prototypage réel. Les résultats obtenus et les analyses de ces trois études sont exposés.

International audience; A pure management approach where all the nodes are managed at any time is too strict for mobile ad-hoc networks. Instead of addressing the management of the whole network, we propose a probabilistic scheme where only a subset of nodes is managed in order to provide a light-weight and efficient management. These nodes are determined based on their network behavior to favor subsets of well connected and network participating nodes. With respect to such a selective management scheme, we derive probabilistic guarantees on the percentage of nodes to be managed. Our contribution is centered on a distributed self-organizing management algorithm at the application layer, its efficient deployment into a management architecture and on a comprehensive simulation study. We will show how to organize the management plane by extracting spatio-temporal components and by selecting manager nodes with several election mechanisms based on degree centrality, eigenvector centrality and K-means paradigm.

Publisher Summary This chapter presents a state of the art of the management of ad-hoc networks. A mobile ad-hoc network (MANET) is a self-organizing network that can be spontaneously deployed by a set of mobile devices (laptops, phones, personal assistants) without requiring a fixed network infrastructure. Ad-hoc networks are a potential solution for the increasing need of mobility and ubiquitous computing. These self-configuring networks are spontaneously deployed by a set of heterogeneous nodes of various capacities and resources, without requiring any preexisting infrastructure. The dynamic and distributed nature of ad-hoc networks raises new challenges towards monitoring and controling them. From an organizational point of view, several models can be considered for the purposes of ad-hoc network management. The recent standardization of ad-hoc routing protocols clarifies the context of ad-hoc networking for defining management approaches. The traditional classification defines five FCAPS functional areas: fault, configuration, accounting, performance, and security. Fault management is not a well-covered area. Issues related to observability are challenging: fault management can be hindered by the impossibility to observe a given node in ad-hoc networks. The constraints of future networks may reverse the tendency: all the optimization approaches defined for ad-hoc networking could be applied to the networks of the future. The growing dynamics of these ones might generate an edge network management crisis.

International audience; We present and analyse a secure protocol for group management, in large and dynamic ad hoc networks. The protocol we suggest relies on the TGDH protocol. In comparison with the previous solution, our algorithm helps to uniformly dispatch the group key calculus on each node, and the global cryptographic tree is optimized. Moreover, we propose an authentication algorithm. Our algorithm provides several well-known security properties, such as nodes authentication, messages freshness, passive attacks resistance and known key attack resistance.

Ad-hoc networks are self-organizing networks that can be spontaneously deployed from a set of mobile devices without requiring any pre-existing fixed infrastructure. Managing such dynamic networks is significantly harder and more complex than managing traditional fixed networks. Indeed, the network topology is dynamic with a high rate of change. Moreover, the network is self-maintained by devices that usually operate under many constraints such as limited battery power, restricted bandwidth and low system capacity. All these factors make traditional management schemes inefficient and expensive. This thesis proposes a new management approach for ad-hoc networks and their services capable to take into account their dynamics and their limited resources. We first design a complete information model capable to represent management data for the spatial, temporal and traffic aspects of ad-hoc networks. Thus, the accurate and comprehensive representation of parameters which drive the evolution of these networks is made possible. We then reorganize the management plane based on a probabilistic scheme, with which the management task is limited to a specific subset of nodes in a light-weight and flexible way. Finally, we adapt the management operations to ad-hoc specifics based on analytical methods such as eigenvector centrality and k-means classification techniques. Our contributions are evaluated through different analytical models, through an extensive set of simulations and through the implementation prototype of a monitoring platform.; Les réseaux ad-hoc sont des réseaux auto-organisés formés spontanément à partir d'un ensemble d'entités mobiles sans nécessiter d'infrastructure fixe pré-existante. La supervision de ces réseaux dynamiques représente une tâche définitivement plus complexe que celle des réseaux traditionnels. En effet, la topologie est soumise à des changements très fréquents. De plus, les stations mobiles sont caractérisées par de multiples contraintes en énergie, bande passante et capacité système. Cette thèse présente une nouvelle approche de gestion pour les réseaux et services ad-hoc capable de prendre en compte leur nature dynamique et leurs ressources limitées. Pour ce faire, nous définissons tout d'abord un modèle d'information de gestion complet et générique permettant d'identifier les éléments caractéristiques d'un tel réseau et de les spécifier à l'aide d'un formalisme commun. Nous décrivons ensuite l'architecture de gestion sous-jacente en proposant une méthode probabiliste permettant une plus grande flexibilité du plan de gestion. Enfin, nous adaptons les opérations de gestion en utilisant différentes méthodes d'analyse telles que l'analyse de la centralité par vecteur propre et la classification par k-means. Ceci nous permet d'établir une vue opérationnelle du réseau et d'évaluer l'état de fonctionnement des noeuds. Nous exploitons autant que possible les informations déjà disponibles dans le plan de routage afin d'aboutir à une solution à faible coût. Indépendamment des modèles analytiques mis en oeuvre, nos contributions ont été évaluées par la simulation et le prototypage.

Ad-hoc networks are self-organizing networks that can be spontaneously deployed from a set of mobile devices without requiring any pre-existing fixed infrastructure. Managing such dynamic networks is significantly harder and more complex than managing traditional fixed networks. Indeed, the network topology is dynamic with a high rate of change. Moreover, the network is self-maintained by devices that usually operate under many constraints such as limited battery power, restricted bandwidth and low system capacity. All these factors make traditional management schemes inefficient and expensive. This thesis proposes a new management approach for ad-hoc networks and their services capable to take into account their dynamics and their limited resources. We first design a complete information model capable to represent management data for the spatial, temporal and traffic aspects of ad-hoc networks. Thus, the accurate and comprehensive representation of parameters which drive the evolution of these networks is made possible. We then reorganize the management plane based on a probabilistic scheme, with which the management task is limited to a specific subset of nodes in a light-weight and flexible way. Finally, we adapt the management operations to ad-hoc specifics based on analytical methods such as eigenvector centrality and k-means classification techniques. Our contributions are evaluated through different analytical models, through an extensive set of simulations and through the implementation prototype of a monitoring platform.; Les réseaux ad-hoc sont des réseaux auto-organisés formés spontanément à partir d'un ensemble d'entités mobiles sans nécessiter d'infrastructure fixe pré-existante. La supervision de ces réseaux dynamiques représente une tâche définitivement plus complexe que celle des réseaux traditionnels. En effet, la topologie est soumise à des changements très fréquents. De plus, les stations mobiles sont caractérisées par de multiples contraintes en énergie, bande passante et capacité système. Cette thèse présente une nouvelle approche de gestion pour les réseaux et services ad-hoc capable de prendre en compte leur nature dynamique et leurs ressources limitées. Pour ce faire, nous définissons tout d'abord un modèle d'information de gestion complet et générique permettant d'identifier les éléments caractéristiques d'un tel réseau et de les spécifier à l'aide d'un formalisme commun. Nous décrivons ensuite l'architecture de gestion sous-jacente en proposant une méthode probabiliste permettant une plus grande flexibilité du plan de gestion. Enfin, nous adaptons les opérations de gestion en utilisant différentes méthodes d'analyse telles que l'analyse de la centralité par vecteur propre et la classification par k-means. Ceci nous permet d'établir une vue opérationnelle du réseau et d'évaluer l'état de fonctionnement des noeuds. Nous exploitons autant que possible les informations déjà disponibles dans le plan de routage afin d'aboutir à une solution à faible coût. Indépendamment des modèles analytiques mis en oeuvre, nos contributions ont été évaluées par la simulation et le prototypage.

Fault detection is a well-known issue in fixed wired networks. Ad-hoc networks provide new challenges towards detecting network failures: the detection task may be hindered by the impossibility to observe a given node. We propose in this paper to monitor the intermittence of network nodes in order to infer network failures. Intermittence can be caused in ad-hoc networks by benign causes due to node mobility and to time-limited out of reachability situations. Abnormal intermittence is however due to faults or malicious network activities. This paper shows how information theoretic measures can identify abnormal intermittence over the routing layer, and proposes a lightweight and distributed intermittence monitoring scheme including several fault detection methods.

Best Student Paper Award; This paper proposes a new management approach for ad-hoc networks based on probabilistic guarantees. Instead of addressing the management of the whole network, we propose a scheme where a subset of nodes is managed in order to provide a light-weight and reliable management. These nodes are determined based on their network behavior to favor subsets of well connected and network participating nodes. With respect to such a selective management scheme, we derive probabilistic guarantees on the percentage of nodes to be managed. Our contribution is centered on a distributed management self-organizing algorithm at the application layer, its efficient deployment into a management architecture as well as on a comprehensive simulation study.

In ad hoc mobile wireless networks, energy consumption is an important issue as most mobile hosts operate on limited battery resource. Existing models for evaluating the energy consumption behavior of a mobile ad hoc network have shown that the various components of energy related costs include transmission power as well as power of reception. In this paper, we extend the model for calculating the energy spent at a node due to a flow in the network. We include the transmission and reception costs if the node belongs to a flow, and reception costs if it is near a flow. The model gives the energy costs of nodes in ideal conditions where interferences and collisions are absent, and hence can be extended to evaluate the effect of interference between flows on energy consumption in more realistic conditions. The collisions due to the flows are also measured, which are used to evaluate the effect of such interference in the energy consumption. We then show how the extra energy spent due to collisions can be calculated by predicting the collisions in the nodes of the network. This prediction is shown to be capable of accurate calculation of the extra energy consumption.

In an ad-hoc network, mobile stations communicate with each other using multi-hop wireless links. There is no stationary infrastructure such as base stations. Each node in the network also acts as a router, forwarding data packets for other nodes. In this architecture, mobile stations have a multi-hop path, via other mobile stations acting as intermediaries or relays, to indirectly forward packets from source to destination. Adjusting the transmitted power is extremely important in ad-hoc networks due to at least the following reasons. The transmitted power of the radio terminals determines the network topology. The network topology in turn has considerable impact on the throughput (fraction of packets, sent by a source, and successfully received at the receiver) performance of the network. The need for power efficiency must be balanced against the lifetime of each individual node and the overall life of the network. Power control problem can be classified in one of three categories. The first class comprises of strategies to find an optimal transmitted power to control the connectivity properties of the network. The second class of approaches could be called power aware routing. Most schemes use some shortest path algorithm with a power based metric, rather than a hop count based metric. The third class of approaches aim at modifying the MAC layer. We use distributed power control algorithms initially proposed for cellular networks. We establish a classification of power control algorithms for wireless ad-hoc networks. We evaluate these algorithms in an IEEE 802.11b multi-hop wireless ad-hoc LAN environment. Results show the advantage of power control in maximizing signal-to-interference ratio and minimizing transmitted power, Dans les réseaux ad-hoc, il n'y a pas d'infrastructure fixe et donc pas de stations de base. Les stations mobiles communiquent directement entre elles en simple saut ou en multi-saut. Chaque station peut agir comme routeur et donc transférer des paquets pour d'autres stations du réseau. La puissance est une ressource précieuse dans les réseaux sans fil en raison de l'autonomie limitée de la batterie et de la relation directe entre l'interférence globale et la capacité du réseau. Un contrôle de puissance efficace économise l'énergie des stations et augmente la capacité d'un réseau sans fil en réduisant l'interférence. Dans notre travail, nous présentons trois catégories de contrôle de puissance pour les réseaux ad-hoc. Une première classe d'algorithmes se base sur la minimisation de la puissance transmise sur chaque lien de chaque route de la source jusqu'à la destination. Une deuxième classe d'algorithmes comporte des stratégies pour trouver la puissance optimale transmise. Ces stratégies sont basées sur le contrôle de la topologie et la connectivité du réseau. Une troisième classe d'algorithmes vise à modifier la couche MAC de sorte à avoir un contrôle de puissance performant. Dans cet article, nous proposons une comparaison et une classification des algorithmes de contrôle de puissance dans les réseaux ad hoc. Enfin, nous évaluons les algorithmes de contrôle de puissance dans un environnement de simulation correspondant à un réseau ad-hoc multi-saut 802.11b/DSSS. Dans le cadre de ces simulations, nous reprenons des modèles existants de contrôle de puissance pour les réseaux cellulaires et nous les appliquons en mode distribué aux réseaux ad-hoc. Les résultats de simulations montrent les limites et les apports des algorithmes de contrôle de puissance dans les réseaux sans fil ad-hoc.

Mobile ad hoc networks have very attractive intrinsic qualities. However they will be adopted only if they are able to support applications with QoS requirements. They must provide a route providing the QoS requested by a flow. The OLSR routing protocol can be extended for that purpose. OLSR relies on multipoint relay (MPR) selection that has an important effect on the routing protocol's performances. Indeed, the overhead generated by the OLSR protocol and more particularly the flooding efficiency depend on MPR selection. Moreover, MPRs are used as intermediate nodes in the routes. The analysis of MPR selection presented in this report gives quantitative results and also takes into consideration QoS support. Simulations on large and dense networks show that our analysis is highly accurate.

Rapport interne.; The increasing interest in deploying infrastructure-less wireless networks based on ad-hoc networking raises new challenges towards monitoring and managing them to provide the optimal possible level of service. We propose in this paper a management architecture based on a filtering and graph dependency analysis in order to evaluate the behavior of mobile ad-hoc networks. We apply an analytical method based on contrast filtering to determine network traffic patterns such as routing paths and a second one based on dependency graphs to estimate node influence in the network as well as to detect misbehaving nodes.

We propose in this paper a self-organized monitoring architecture for mobile ad-hoc networks based on a selective scheme where subsets of nodes are managed. These nodes are determined based on their network behavior in order to favor subsets of well-connected nodes. The key idea is to relax the requirements of the management plane, and to use these manageable subsets to monitor the performance of the overall network. We therefore propose a new performance metric to be monitored, in order to estimate the capability of ad-hoc nodes to communicate end-to-end in the network. Extensive simulations show how different parameters affect this metric.

Mobile ad-hoc networks (MANETs) have many advantages, self-adaptivity for instance, that make them attractive for multiple applications. Most of these networks use the MAC 802.11b protocol for the medium access control. As all nodes use the same transmission frequency, interferences can occur compromising the quality of service (QoS) provided to flows. In this report, we show how to evaluate the bandwidth required at the MAC level for a flow whose characteristics are known at the application level. The bandwidth evaluation on a node accounts for the interferences due to the flow itself and the other flows. This evaluation has been validated by confrontation with results obtained by NS-2 simulations. We then propose an efficient admission control based on this evaluation. An example illustrates the proposed solution and highlights the accuracy of the evaluation.

Routing protocols are the main issue of ad hoc networks. Because flat propositions (reactive, proactive) are not sufficient and suffer of lack of performance, new solutions should be investigated and proposed. In the other hand, self-organization propose to structure the network by creating a hierarchy between the strongest and the weakest nodes. We propose a new routing protocol, Virtual Structure Routing (VSR), based on a self-organization point of view: a virtual topology including both a backbone and clusters. The backbone is used to collect control traffic and to reduce overhead for route discovering. VSR uses clusters to define a route as a list of clusters Id. This cluster topology is more stable than the physical topology. Hence, routes are more robust. VSR combines the assets of both flat approaches: intra-cluster routing is proactive while inter-cluster routing is reactive. Finally, routes are computed dynamically and a mechanism of route repair is proposed., Le routage est le problème essentiel dans les réseaux ad-hoc. Cependant, les ap-proches de routage à plat, tant réactives que proactives, présentent une faible capacité à pas-ser à l'échelle : les performances décroissent rapidement dès que le nombre de participants ou de communications simultanées devient important. Par ailleurs, les mécanismes d'auto-configuration de réseaux ad hoc permettent de structurer le réseau en créant une hiérarchie. Nous proposons ici un nouveau protocole de routage, Virtual Structure Routing (VSR), tirant parti d'une auto-organisation de type topologie virtuelle constituée d'une dorsale et de zones de services. La dorsale permet de collecter le trafic de contrôle et d'en limiter le surcoût en messages. VSR utilise les zones de service pour définir une route comme une suite d'identifiants de zones. Les zones de service permettent de créer une vue logique du réseau plus stable que la topologie physique, créant des routes plus persistantes dans le temps et donc plus robustes. De plus, VSR combine les avantages des deux approches à plat : le routage intra-cluster est proac-tif tandis que celui inter-cluster est réactif. Enfin, nous proposons également un mécanisme de reconstruction de routes afin de limiter les pertes de paquets.

In this paper we present an analytical procedure for the computation of the node isolation probability in an ad-hoc network in presence of channel randomness, with applications to shadowing and fading phenomena. Such a probability coincides with the complement of the coverage probability, given that nodes are distributed according to a Poisson point process. These results are used to obtain an estimate of the connectivity features for very dense networks. For the case of superimposed lognormal shadowing and Rayleigh fading, the connectivity improvements achievable by means of diversity schemes are investigated.

International audience; Ad hoc network normally has critical connectivity properties before partitioning. The timely recognition is important in order to perform some data or service replication. Several existing centralized or globalized algorithms declare an edge or a node as critical if their removal will separate the network into several components. We introduce several localized definitions of critical nodes and critical links, using topological or positional information. A node is critical if the subgraph of k-hop neighbours of node (without the node itself) is disconnected. We propose three definitions of critical links, based on verifying common k-hop neighbours, loop length, and critical status of link endpoints, respectively. The experiments with random unit graph model of ad hoc networks show high correspondence of local and global decisions. For instance, in experiments with 500 nodes in connected random unit graphs, over half of locally estimated critical nodes and links were indeed globally critical even for k=1 (the accuracy increases to over 70% for k=2 and over 80% for k=3), for average number of neighbours ranging from 3 to 15. The errors mostly occur when alternative routes exist but are relatively long, and therefore may not provide satisfactory service in applications. Therefore our localized protocols provide faster and often more reliable partition warnings for possible timely replication decisions.

International audience; Least interference routing for wireless ad-hoc networks

International audience; Ad hoc networks are autonomous dynamic networks composed of mobile devices like personal digital assistants (PDA) for instance. In such mobile networks, lack of infrastructure leads to non trivial information discovery and dissemination. A scheme in which a unique object centralizes information is not efficient for many reasons. In this paper, we propose a probabilistic algorithm to satisfactorily distribute an information token among nodes forming the network by using localized datas. Then, in order to limit the number of memorizing nodes, we propose to make memorize nodes belonging to a dominating set

Rapport interne.; The increasing interest in providing infrastructure-less wireless networks based on ad-hoc networking raises new challenges towards providing them the required quality of service. While standard QoS metrics apply gracefully to fixed infrastructures, new metrics need to be considered in the management of ad-hoc networks. We propose in this paper a new QoS metric taking into account the possible average coverage in an ad-hoc network. This metric corresponds to the average number of nodes that a node can reach in the network. We describe a management architecture capable to monitor this metric together with the network density. Our framework can dynamically configure the routing protocol to assure that the QoS level is optimal i.e. to maximize the number of reachable nodes in the network.

International audience; Link state has been the dominating IGP routing technology in IP networks for more than a decade. With the advent of wireless ad-hoc networking, the need for light, efficient and robust routing makes it a good candidate to be also used in this constrained environment. One of the key issue in ad-hoc networking is the lack of bandwidth. Thus, in this paper we examine the overhead due to link state routing in an ad-hoc network. More precisely we study the classic link-state protocol OSPF and OLSR, a link state protocol that was developed specifically for ad-hoc networks. Further, we study how this overhead evolves when the node density increases. The last part of the paper presents directions towards extending OSPF for wireless and ad-hoc networks, which would make it a favorite to seamlessly unify wired and mobile IP networks.

International audience; This paper deals with piconet topology issues in IEEE 802.15.3 High Rate Wireless Personal Area Network standard. These issues preventing two devices to establish a connection come from the coexistence of two conflicting concepts : ad-hoc networking and centralized coordination. An algorithm for the initialization of the topology of the piconet is proposed. This algorithm leads to a probability higher than 95% of connection success in the whole power emission range defined by the standard.

International audience; A classical problem caused by nodes movement in an ad hoc network is partitioning. Predicting those partitions could be a very useful feature that can be provided to applications in a mobile ad-hoc network environment. Indeed, being aware of a future disconnection in the net- work can help to ensure a better quality of service by adapting the application behavior. Algorithms already exists to do this but they need position information to be provided by a positioning system. This paper propose an original link robustness evaluation method based on the notion of disjoint paths which allow efficient partition detection without using any kind of positioning system.

Stage fin d'etudes . Rapport de stage.; L'agent de supervision par politiques ainsi réalisé pour le protocole BRuIT permet de gérer les réservations de la bande passante dans un réseau ad hoc par des politiques qui tiennent en compte la mobilité, l'état des ressources et les interférences radio. La conception de l'agent de supervision et faite de telle façon à supporter les changements apportés au protocole BRuIT dans des versions prochaines. Les messages de signalisation qui passent au serveur de politiques parviennent à l'agent de supervision à travers une connexion UDP ce qui permet l'indépendance entre le module de signalisation et le module de gestion. Toutefois, l'agent de supervision ne réalise pas la sécurité des communications avec le serveur de politiques. Une plate forme de gestion ad hoc à base de politiques serait plus adaptée pour administrer de manière plus efficace un réseau ad hoc. Chaque noeud du réseau peut jouer le rôle d'un serveur de politiques. Une plate forme qui est un ensemble de noeuds est alors organisée selon la topologie du réseau de telle façon que toute machine pourrait communiquer avec un serveur de politiques à tout moment. Cette plate forme a la particularité d'être dynamique : elle s'adapte à la topologie du réseau, et facilite l'accès des noeuds du réseau aux serveurs de politiques.

This report proposes an adaptive service differentiation scheme for QoS enhancement in IEEE 802.11 wireless ad hoc networks. Our approach, called Adaptive Enhanced Distributed Coordination Function (AEDCF), is derived from the new EDCF introduced in the upcoming IEEE 802.11e standard. One of the main problems of EDCF is the static reset of the Contention Window (CW) which decreases significantly the throughput performance and increases the collision rate specially at high load conditions. Our scheme aims to share the transmission channel efficiently while providing different priorities to access the wireless medium. Relative priorities are provisioned by adjusting the size of the Contention Window (CW) of each traffic class taking into account both applications requirements and network conditions. We have implemented AEDCF in the NS-2 network simulator. Several simulation scenarios have been used to evaluate its performance and to determine the optimal value of certain parameters. We analyse through simulations the efficiency of the slow and adaptive decrease of the CW after each successful transmission and compare it with the classic scheme proposed in the standard. Results show that AEDCF outperforms the basic EDCF, especially at high load conditions- . Indeed, our scheme increases the medium utilization ratio and reduces for more than 50 rate. While achieving delay differentiation, low jitter is also maintained, and the overall goodput obtained is up to 20 Moreover, the complexity of AEDCF remains similar to the EDCF scheme, enabling the design of cheap implementations.

For commercial availability reasons, most actual multi-hops ad-hoc simulations and test-beds are based on IEEE 802.11 standard \cite{80211} and its medium access method CSMA/CA. But this standard has not been designed for that kind of network and presents serious flaws in this context. In this paper, we shall try to highlight problems that can appear in the \textbf{non-direct} neighborhood of important data flows in ad-hoc networks. In some situations, the fairness of the medium access can indeed be very poor. Various techniques could be used to solve this problem. In this paper we present one solution, which only requires minor modifications to the standard.; Pour des raisons de disponibilité commerciale, la plupart des simulations et des bancs d’essai de réseaux ad-hoc multi-sauts sont réalisés avec l’aide de la norme IEEE 802.11 et de sa méthode d’accès au médium CSMA/CA. Mais cette norme n’a pas été conçue à l’origine pour ce type de réseau, et présente dans ce contexte des problèmes sérieux. Dans ce rapport de rechercher, nous allons mettre en lumière certains des problèmes qui apparaissent au voisinage de flux importants dans les réseaux adhoc multi-sauts Dans certaines situations, l’équité de l’accès au médium peut en effet être très mauvaise. De nombreuse techniques peuvent être utilisées pour résoudre ces problèmes. Nous présenterons ici un solution qui à, entre autres avantages, de ne nécessiter que des mofifications mineures à la norme