7 research outputs found

    SLSF: Stable Linked Structure Flooding For Mobile Ad Hoc Networks

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    International audienceFor some applications in ad hoc networks optimal dissemination is a key issue (e.g. service discovery, network management). In this paper, we are creating and exploiting stable (sub-)structures to achieve an efficient (as far as low network resource usage is concerned) dissemination by building a two-layer protocol. Firstly, single-hop clusters, among stable-connected devices, are created. Secondly, on top of those clusters, inter-cluster relays (ICR) are determined. This leads to an overall stable-connected structure. The results show that the proposed stable linked structure flooding (SLSF) protocol efficiently disseminates data among stable nodes. Interestingly with growing density both the number of forwarding nodes and the bandwidth used remain comparatively low. Therefore we plan to use SLSF as a basis for a stable service discovery

    OLSR and WCPD as Basis for Service Discovery in MANETs

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    ISBN : 978-0-7695-3367-4International audienceService discovery is one of the most fundamental building blocks of self-organization. While mature approaches exist in the realm of fixed networks, they are not directly applicable in the context of MANETs. We investigate and compare two different protocols as basis for service discovery, namely OLSR and WCPD. OLSR is a proactive routing protocol while WCPD is a path discovery protocol integrating node and link stability criteria. Two conflicting objectives of service discovery are the coverage of service queries together with the required bandwidth. Simulations are performed based on a setting in a city center with human mobility. We show that OLSR outperforms WCPD in terms of coverage. Due to its proactive nature, however, bandwidth consumption is high. WCPD on the other hand is much more bandwidth efficient, but at the cost of lower coverage.Finally, we motivate employing OLSR on top of an overlay topology maintained by WCPD. This fosters stability while reducing overhead and keeping coverage high

    Stabilizing cluster structures in mobile networks for OLSR and WCPD as Basis for Service Discovery

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    International audienceService discovery is one of the most fundamental building blocks of self-organization. While mature approaches exist in the realm of fixed networks, they are not directly applicable in the context of MANETs. We investigate and compare two different protocols as basis for service discovery, namely OLSR and WCPD. OLSR is a proactive routing protocol while WCPD is a path discovery protocol integrating node and link stability criteria. Two conflicting objectives of service discovery are the coverage of service queries together with the required bandwidth. Simulations are performed based on a setting in a city center with human mobility. We show that OLSR outperforms WCPD in terms of coverage. Due to its proactive nature, however, bandwidth consumption is high. WCPD on the other hand is much more bandwidth efficient, but at the cost of lower coverage. Finally, we motivate employing OLSR on top of an overlay topology maintained by WCPD. This fosters stability while reducing overhead and keeping coverage high. As a first step towards a hybrid protocol, we aim at increasing the stability of the communication paths. To do so, an adaptive approach is used, which increases the robustness of the network topology structures

    Prototype d'architecture de découverte de services avancée

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    This document describes the implementation and tools used for the service discovery architecture described in [1]. We describe the tool, JANE, used for our simulations and the final architecture. As service discovery protocol we used Zeroconf and depict which changes had to be made to an existing implementation. We used an underlying clustering structure, NLWCA, as dissemination overlay. Finally we show the building blocks of the service discovery architechture of a device

    Intégration des services à la plateforme pour démonstrateurs

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    Livrable L5.2, Sous-Projet 5 (SP 5) : ExpĂ©rimentationsCe document vise la dĂ©finition des scenarii d'usage dans le projet SARAH, comprenant la manipulation de flux multimĂ©dias sur les rĂ©seaux ad hoc ainsi que la localisation de l'utilisateur par rapport aux services et utilisateurs de voisinage et Ă  distance. Les scenarii dĂ©crivent principalement les expĂ©rimentations et dĂ©monstrateurs dans le cadre du SP5. Certains scenarii dĂ©crits dans ce document peuvent servir de support Ă  la validation de composants issus des labos des partenaires (simulation ou petits testbeds) dans les diffĂ©rents sous-projets. De plus, certains scĂ©narii peuvent ne pas ĂȘtre rĂ©utilisĂ©s dans les SPs, mais prĂ©sentent un intĂ©rĂȘt pour de futurs dĂ©ploiements de services sur rĂ©seaux ad hoc sans fil

    Route discovery schemes in Mobile Ad hoc Networks with variable-range transmission power

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    Broadcasting in MANETs is important for route discovery but consumes significant amounts of power that is difficult to renew for devices that rely heavily on batteries. Most existing routing protocols make use of a broadcast scheme known as simple flooding. In such an on-demand routing protocol (e.g. AODV) the source node originates a Route Request (RREQ) packet that is blindly rebroadcast via neighbouring nodes to all nodes in the network. Simple flooding leads to serious redundancy, together with contention, and collisions, which is often called the broadcast storm problem. This thesis proposes two improvement strategies: topology control (adjusting transmission power) and reduced retransmissions (reducing redundant rebroadcasts) to reduce energy consumption. For energy efficient route discovery the main idea is to reduce the energy consumed per broadcast during route discovery. An Energy Efficient Adaptive Forwarding Algorithm (called EEAFA) is proposed to reduce the impact of RREQ packet flooding in on-demand routing protocols. The algorithm operates in two phases: 1) Topology construction phase, which establishes a more scalable and energy efficient network structure where nodes can adjust their transmission power range dynamically, based on their local density. 2) A Forwarding Node Determination phase, that utilises network information provided by the constructed topology, where nodes independently decide to forward a RREQ packet or not without relying on GPS or any distance calculations. A further Enhanced EEAFA (called E-EEAFA) algorithm is also proposed, which combines two techniques: graph colouring and sectoring techniques. Graph colouring increases awareness at network nodes to improve the determination of a forwarding node, while the sectoring technique divides neighbours into different forwarding sectors. This helps to reduce overlap between forwarding nodes and select suitable nodes in each sector to forward RREQ packets. These techniques are employed in a distributed manner and collaborate to reduce the number of forwarding nodes, which thus reduces the volume of RREQ packets populating the network. These algorithms have been validated as effective by NS2 simulation studies that are detailed in the thesis
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