195 research outputs found

    A Load-Balancing and Push-out Scheme for Supporting QoS in MANETs

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    Currently, mobile ad hoc networks (MANETs) lack load-balancing capabilities, and thus, they fail to provide good performance especially in the case of a large volume of traffic. Ad hoc networks lack also service differentiation. However, in these wireless environments, where channel conditions are variable and bandwidth is scarce, the differentiated services developed for the Internet are suboptimal without lower layers' support. The IEEE 802.11 standard for Wireless LANs is the most widely used WLAN standard today. It has a mode of operation that can be used to provide service differentiation, but it has been shown to perform badly. In this paper, we present a simple but very effective method for support Quality of Service, by the use of load-balancing and push-out scheme. This approach offers to the mobile node: the ability to alleviate congestion by traffic distribution of excessive load, and to support priority of packets in the single MAC buffer. We evaluate the performance of our algorithm and compare it with the original IEEE 802.11b protocol. Simulation results show that this new approach reduces packet loss rate and increases throughput as well as provides service differentiation in the MAC layer

    InfiniBand-Based Mechanism to Enhance Multipath QoS in MANETs

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    Mobile Ad-hoc Networks (MANETs), the continuous changes in topology and the big amounts of data exchanged across the network makes it difficult for a single routing algorithm to route data efficiently between nodes. MANETs usually suffer from high packet loss rates and high link failure rates, which also makes it difficult to exchange data in effective and reliable fashion. These challenges usually increase congestion on some links while other links are almost free. In this thesis, we propose a novel mechanism to enhance QoS in multipath routing protocols in MANETs based on the InfiniBand (IB) QoS architecture. The basic idea of our approach is to enhance the path balancing to reduce congestion on overloaded links. This mechanism has enabled us to give critical applications higher priority to send them packet when routing their packets across the network, effectively manage frequent connections and disconnections and thus help reduce link failures and packet loss rates, and reduce the overall power consumption as a consequence of the previous gains. We have tested the scheme on the (IBMGTSim) simulator and achieved significant improvements in QoS parameters compared to two well-known routing protocols: AODV and AOMDV.هناك نوع من الشبكات حيث يكون كل المكونات فيها عبارة عن اجهزة متحركة بدون اي بنية تحتية تسمى "MANET "في هذا النوع من الشبكات تتعاون االجهزة ذاتيا لتحديد الطرق في ما بينها والنها متحركة تقوم هذه االجهزة بحساب اكثر من طريق عو ًضا عن حساب طريق واحد لتقليل من احتمالية فشل في االرسال حيث اذا تم فشل في طريق معينة تبقى الطرق االخرة سليمة. وفي ناحية اخرى ولتنوع اهمية البرامج والخدمات التي توفرها هذه االجهزة هناك ما يسمى "بجودى الخدمات Service of Quality" حيث يقوم المستخدم بوضع اولويات للبرامج والخدمات من استهالك المصادر المتاحة, والطريق الشائعة هي ان يقوم المستخدم بوضع حدود على سرعة استعمال الشبكة من قبل البرامج االقل اهمية لترك المصادر متاحة للبرامج الاكثر المهمة بشكل اكثر وهذا الحل يحتوي على الكثير من المشاكل في هذا النوع من الشبكات, حيث ان مواصفات الطرق غير معروفة وغير ثابتة وقد تحتوي او تتغير الى قيم اقل من الحدود الموضوعة للبرمج الغير مهمة فتتساوى البرامج والخدمات االقل اهمية بالبرامج االكثر اهمية مما يعني فشل في جودة الخدمات. من خالل بحثنا عن حلول ودراسة انواع مختلفة من الشبكات وجدنا نوع من تطبيق جودة الخدمات في نوع الشبكات المسمى بInfiniBand حيث يتم تطبيق جودة الخدمات من خالل تغيير عدد الرسال المبعثة من قبل البرامج, حيث تقوم االجهزة بارسال عدد اكبر من الرسال التابعة للبرامج المهمة مقارنة بعدد الرسال التابعة للبرامج االقل اهمية, ويتم ذلك باستخدام الصفوف, حيث تصطف الرسال من البرامج المهمة بصف يختلف عن الصف الذي يحتوي على رسال البرامج الغير مهمة. هذا الحل له فائدتان مهمتان االولى انه ال يوثر عالطريقة التقليدية ويمكن ان يستخدم معها والفائدة الثانية انه وبخالف الطريقة التقليدية, الطريقة الجديدة ال تتاثر بصفات الطريق المحسوبة او بتغير صفاتها فنسبة عدد الرسال تكون نفسها مهما اختلفت الطرق و صفاتها, بعد تطبيق هذا النوع وجددنا تحسين في كفائة االرسال تصل الى 18 %في جودة التوصيل و 10 %في سرعة الوصول مع العلم ان جودة الخدمات لم تفشل على غرار الطريقة التقليدية

    Survey And New Approach In Service Discovery And Advertisement For Mobile Ad Hoc Networks.

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    Service advertisement and discovery is an important component for mobile adhoc communications and collaboration in ubiquitous computing environments. The ability to discover services offered in a mobile adhoc network is the major prerequisite for effective usability of these networks. This paper aims to classify and compare existing Service Discovery (SD) protocols for MANETs by grouping them based on their SD strategies and service information accumulation strategies, and to propose an efficient approach for addressing the inherent issues

    Quality management of surveillance multimedia streams via federated SDN controllers in Fiwi-iot integrated deployment environments

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    Traditionally, hybrid optical-wireless networks (Fiber-Wireless - FiWi domain) and last-mile Internet of Things edge networks (Edge IoT domain) have been considered independently, with no synergic management solutions. On the one hand, FiWi has primarily focused on high-bandwidth and low-latency access to cellular-equipped nodes. On the other hand, Edge IoT has mainly aimed at effective dispatching of sensor/actuator data among (possibly opportunistic) nodes, by using direct peer-to-peer and base station (BS)-assisted Internet communications. The paper originally proposes a model and an architecture that loosely federate FiWi and Edge IoT domains based on the interaction of FiWi and Edge IoT software defined networking controllers: The primary idea is that our federated controllers can seldom exchange monitoring data and control hints the one with the other, thus mutually enhancing their capability of end-to-end quality-aware packet management. To show the applicability and the effectiveness of the approach, our original proposal is applied to the notable example of multimedia stream provisioning from surveillance cameras deployed in the Edge IoT domain to both an infrastructure-side server and spontaneously interconnected mobile smartphones; our solution is able to tune the BS behavior of the FiWi domain and to reroute/prioritize traffic in the Edge IoT domain, with the final goal to reduce latency. In addition, the reported application case shows the capability of our solution of joint and coordinated exploitation of resources in FiWi and Edge IoT domains, with performance results that highlight its benefits in terms of efficiency and responsiveness

    Service Replication in Wireless Mobile Ad Hoc Networks

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    Die vorliegende Arbeit beschäftigt sich mit dem Management von Diensten im mobilen ad-hoc Netzwerken (MANETs). MANETs sind drahtlose Netzverbände mobiler Einheiten die sich dezentral ohne eine übergeordnete Organisation selbst verwalten. Die Netztopologie eines MANET verändert sich dabei dynamisch mit der Bewegung der autonomen Teilnehmer. Sensor Netzwerke, Personal Area Networks und Satelliten Netzwerke sind typische Beispiele für derartige MANETs. Mit der wachsenden Bedeutung der drahtlosen Vernetzung mobiler Geräte haben sich MANETs in den vergangenen Jahren zu einem wichtigen Forschungsgebiet entwickelt. Im Katastrophenmanagement, bei zivilen Rettungsfällen oder in militärischen Szenarien kann ihre infrastrukturlose Selbstorganisation MANETs zum einzig möglichen Kommunikationsmittel machen. Die mobilen Knoten eines MANETs kooperieren um essenzielle Netzwerkdienste wie das Routing und den Datentransport gemeinschaftlich zu gewährleisten. Ressourcen wie die Bandbreite zwischen Knoten, die Rechenleistung der mobilen Geräte und ihre Batterieleistung sind dabei typischerweise stark begrenzt und zudem wechselnd. Das Teilen der verfügbaren Ressourcen ist daher eine Notwendigkeit für das effiziente Funktionieren eines MANETs. Dienstorientierte Architekturen (SOAs) stellen ein geeignetes Paradigma dar, um geteilte Ressourcen zu verwalten. Wenn verfügbare Ressourcen als Dienst aufgefasst werden, lässt sich ihre Nutzung als Dienstabfrage bearbeiten. In diesem Zusammenhang ermöglichen SOAs Abstraktion, Kapselung, lose Koppelung, Auffindbarkeit von Ressourcen und dir für MANETs essenzielle Autonomie. Die Anwendung von SOAs auf MANETs findet daher zunehmend Beachtung in der Forschung

    From MANET to people-centric networking: Milestones and open research challenges

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    In this paper, we discuss the state of the art of (mobile) multi-hop ad hoc networking with the aim to present the current status of the research activities and identify the consolidated research areas, with limited research opportunities, and the hot and emerging research areas for which further research is required. We start by briefly discussing the MANET paradigm, and why the research on MANET protocols is now a cold research topic. Then we analyze the active research areas. Specifically, after discussing the wireless-network technologies, we analyze four successful ad hoc networking paradigms, mesh networks, opportunistic networks, vehicular networks, and sensor networks that emerged from the MANET world. We also present an emerging research direction in the multi-hop ad hoc networking field: people centric networking, triggered by the increasing penetration of the smartphones in everyday life, which is generating a people-centric revolution in computing and communications

    5G and beyond networks

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    This chapter investigates the Network Layer aspects that will characterize the merger of the cellular paradigm and the IoT architectures, in the context of the evolution towards 5G-and-beyond, including some promising emerging services as Unmanned Aerial Vehicles or Base Stations, and V2X communications

    A COMMUNICATION FRAMEWORK FOR MULTIHOP WIRELESS ACCESS AND SENSOR NETWORKS: ANYCAST ROUTING & SIMULATION TOOLS

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    The reliance on wireless networks has grown tremendously within a number of varied application domains, prompting an evolution towards the use of heterogeneous multihop network architectures. We propose and analyze two communication frameworks for such networks. A first framework is designed for communications within multihop wireless access networks. The framework supports dynamic algorithms for locating access points using anycast routing with multiple metrics and balancing network load. The evaluation shows significant performance improvement over traditional solutions. A second framework is designed for communication within sensor networks and includes lightweight versions of our algorithms to fit the limitations of sensor networks. Analysis shows that this stripped down version can work almost equally well if tailored to the needs of a sensor network. We have also developed an extensive simulation environment using NS-2 to test realistic situations for the evaluations of our work. Our tools support analysis of realistic scenarios including the spreading of a forest fire within an area, and can easily be ported to other simulation software. Lastly, we us our algorithms and simulation environment to investigate sink movements optimization within sensor networks. Based on these results, we propose strategies, to be addressed in follow-on work, for building topology maps and finding optimal data collection points. Altogether, the communication framework and realistic simulation tools provide a complete communication and evaluation solution for access and sensor networks

    Mobile Ad-Hoc Networks

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    Being infrastructure-less and without central administration control, wireless ad-hoc networking is playing a more and more important role in extending the coverage of traditional wireless infrastructure (cellular networks, wireless LAN, etc). This book includes state-of-the-art techniques and solutions for wireless ad-hoc networks. It focuses on the following topics in ad-hoc networks: quality-of-service and video communication, routing protocol and cross-layer design. A few interesting problems about security and delay-tolerant networks are also discussed. This book is targeted to provide network engineers and researchers with design guidelines for large scale wireless ad hoc networks
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