2,381 research outputs found
Design and Implementation of a Measurement-Based Policy-Driven Resource Management Framework For Converged Networks
This paper presents the design and implementation of a measurement-based QoS
and resource management framework, CNQF (Converged Networks QoS Management
Framework). CNQF is designed to provide unified, scalable QoS control and
resource management through the use of a policy-based network management
paradigm. It achieves this via distributed functional entities that are
deployed to co-ordinate the resources of the transport network through
centralized policy-driven decisions supported by measurement-based control
architecture. We present the CNQF architecture, implementation of the prototype
and validation of various inbuilt QoS control mechanisms using real traffic
flows on a Linux-based experimental test bed.Comment: in Ictact Journal On Communication Technology: Special Issue On Next
Generation Wireless Networks And Applications, June 2011, Volume 2, Issue 2,
Issn: 2229-6948(Online
Design and implementation of architectures for the deployment of secure community wireless networks
Recientes avances en las tecnologías de la comunicación, así como la proliferación de nuevos dispositivos de computación, están plasmando nuestro entorno hacia un Internet ubicuo. Internet ofrece una plataforma global para acceder con bajo coste a una vasta gama de servicios de telecomunicaciones, como el correo electrónico, comercio electrónico, tele-educación, tele-salud y tele-medicina a bajo coste. Sin embargo, incluso en los países más desarrollados, un gran número de áreas rurales todavía están pobremente equipadas con una infraestructura básica de telecomunicaciones. Hoy en día, existen algunos esfuerzos para resolver esta falta de infraestructura, pero resultan todavía insuficientes.
Con este objetivo presentamos en esta tesis RuralNet, una red comunitaria inalámbrica para proveer acceso a Internet de forma personalizada a los subscriptores de un área rural. Los objetivos de este estudio han sido el desarrollo de una nueva arquitectura para ofrecer un acceso a Internet flexible y seguro para zonas rurales aisladas. RuralNet combina el paradigma de las redes mesh y el uso de los dispositivos inalámbricos embebidos más económicos para ofrecer un gran número de servicios y aplicaciones basados en Internet. La solución desarrollada por RuralNet es capaz de cubrir grandes áreas a bajo coste, y puede también ser fácilmente desplegado y extendido tanto en términos de cobertura como de servicios ofrecidos.
Dado que la implementación y la evaluación de RuralNet requiere un alto coste y una gran cantidad de mano de obra, hemos considerado que la simulación y la emulación eran una alternativa válida para ahorrar costes. Con este objetivo hemos desarrollado Castadiva, un emulador flexible proyectado para la evaluación de redes MANET y mesh. Castadiva es un emulador basado en dispositivos de bajo coste, utilizado para evaluar los protocolos y las aplicaciones desarrolladas.Hortelano Otero, J. (2011). Design and implementation of architectures for the deployment of secure community wireless networks [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/10079Palanci
Integrated Architecture for Configuration and Service Management in MANET Environments
Esta tesis nos ha permitido trasladar algunos conceptos teóricos de la computación ubicua a escenarios reales, identificando las necesidades específicas de diferentes tipos de aplicaciones. Con el fin de alcanzar este objetivo, proponemos dos prototipos que proporcionan servicios sensibles al contexto en diferentes entornos, tales como conferencias o salas de recuperación en hospitales. Estos prototipos experimentales explotan la tecnología Bluetooth para ofrecer información basada en las preferencias del usuario. En ambos casos, hemos llevado a cabo algunos experimentos con el fin de evaluar el comportamiento de los sistemas y su rendimento.
También abordamos en esta tesis el problema de la autoconfiguración de redes MANET basadas en el estándar 802.11 a través de dos soluciones novedosas. La primera es una solución centralizada que se basa en la tecnología Bluetooth, mientras la segunda es una solución distribuida que no necesita recurrir a ninguna tecnología adicional, ya que se basa en el uso del parámetro SSID. Ambos métodos se han diseñado para permitir que usuarios no expertos puedan unirse a una red MANET de forma transparente, proporcionando una configuración automática, rápida, y fiable de los terminales. Los resultados experimentales en implementaciones reales nos han permitido evaluar el rendimiento de las soluciones propuestas y demostrar que las estaciones cercanas se pueden configurar en pocos segundos. Además, hemos comparado ambas soluciones entre sí para poner de manifiesto las diferentes ventajas y desventajas en cuanto a rendimento.
La principal contribución de esta tesis es EasyMANET, una plataforma ampliable y configurable cuyo objetivo es automatizar lo máximo posible las tareas que afectan a la configuración y puesta en marcha de redes MANET, de modo que su uso sea más simple y accesible.Cano Reyes, J. (2012). Integrated Architecture for Configuration and Service Management in MANET Environments [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/14675Palanci
Self-organizing Network Optimization via Placement of Additional Nodes
Das Hauptforschungsgebiet des Graduiertenkollegs "International Graduate
School on Mobile Communication" (GS Mobicom) der Technischen Universität
Ilmenau ist die Kommunikation in Katastrophenszenarien. Wegen eines
Desasters oder einer Katastrophe können die terrestrischen Elementen der
Infrastruktur eines Kommunikationsnetzwerks beschädigt oder komplett
zerstört werden. Dennoch spielen verfügbare Kommunikationsnetze eine sehr
wichtige Rolle während der Rettungsmaßnahmen, besonders für die
Koordinierung der Rettungstruppen und für die Kommunikation zwischen ihren
Mitgliedern. Ein solcher Service kann durch ein mobiles Ad-Hoc-Netzwerk
(MANET) zur Verfügung gestellt werden. Ein typisches Problem der MANETs
ist Netzwerkpartitionierung, welche zur Isolation von verschiedenen
Knotengruppen führt. Eine mögliche Lösung dieses Problems ist die
Positionierung von zusätzlichen Knoten, welche die Verbindung zwischen den
isolierten Partitionen wiederherstellen können. Hauptziele dieser Arbeit
sind die Recherche und die Entwicklung von Algorithmen und Methoden zur
Positionierung der zusätzlichen Knoten. Der Fokus der Recherche liegt auf
Untersuchung der verteilten Algorithmen zur Bestimmung der Positionen für
die zusätzlichen Knoten. Die verteilten Algorithmen benutzen nur die
Information, welche in einer lokalen Umgebung eines Knotens verfügbar ist,
und dadurch entsteht ein selbstorganisierendes System. Jedoch wird das
gesamte Netzwerk hier vor allem innerhalb eines ganz speziellen Szenarios -
Katastrophenszenario - betrachtet. In einer solchen Situation kann die
Information über die Topologie des zu reparierenden Netzwerks im Voraus
erfasst werden und soll, natürlich, für die Wiederherstellung mitbenutzt
werden. Dank der eventuell verfügbaren zusätzlichen Information können
die Positionen für die zusätzlichen Knoten genauer ermittelt werden. Die
Arbeit umfasst eine Beschreibung, Implementierungsdetails und eine
Evaluierung eines selbstorganisierendes Systems, welche die
Netzwerkwiederherstellung in beiden Szenarien ermöglicht.The main research area of the International Graduate School on Mobile
Communication (GS Mobicom) at Ilmenau University of Technology is
communication in disaster scenarios. Due to a disaster or an accident, the
network infrastructure can be damaged or even completely destroyed.
However, available communication networks play a vital role during the
rescue activities especially for the coordination of the rescue teams and
for the communication between their members. Such a communication service
can be provided by a Mobile Ad-Hoc Network (MANET). One of the typical
problems of a MANET is network partitioning, when separate groups of nodes
become isolated from each other. One possible solution for this problem is
the placement of additional nodes in order to reconstruct the communication
links between isolated network partitions. The primary goal of this work is
the research and development of algorithms and methods for the placement of
additional nodes. The focus of this research lies on the investigation of
distributed algorithms for the placement of additional nodes, which use
only the information from the nodes’ local environment and thus form a
self-organizing system. However, during the usage specifics of the system
in a disaster scenario, global information about the topology of the
network to be recovered can be known or collected in advance. In this case,
it is of course reasonable to use this information in order to calculate
the placement positions more precisely. The work provides the description,
the implementation details and the evaluation of a self-organizing system
which is able to recover from network partitioning in both situations
Concept and design of the hybrid distributed embedded systems testbed
Wireless mesh networks are an emerging and versatile communication technology.
The most common application of these networks is to provide access of any
number of users to the world wide Internet. They can be set up by Internet
service providers or even individuals joined in communities. Due to the
wireless medium that is shared by all participants, effects like short-time
fading, or the multi-hop property of the network topology many issues are
still in the focus of research. Testbeds are a powerful tool to study wireless
mesh networks as close as possible to real world application scenarios. In
this technical report we describe the design, architecture, and implementation
of our work-in-progress wireless testbed at Freie Universität Berlin
consisting of 100 mesh routers that span multiple buildings. The testbed is
hybrid as it combines wireless mesh network routers with a wireless sensor
network
Mesh networks for handheld mobile devices
Mesh communications emerge today as a very popular networking solution. Mesh
networks have a decentralized and multihop design. These characteristics arouse
interest in research for relevant novel features, such as cooperation among nodes,
distribution of tasks, scalability, communication with limited infrastructure support,
and the support of mobile devices as mesh nodes.
In addition to the inexistence of a solution that implements mesh networks with
mobile devices at the data link layer (Layer 2), there is also a need to reconsider
existing metrics with new information to tackle the intrinsic characteristics of mobile
devices, e.g., the limited energy resources of their battery.
To tackle this problem, this thesis presents a detailed study about projects, routing
protocols and metrics developed in the area of mesh networks. In addition, two data
link layer solutions, Open802.11s and B.A.T.M.A.N-advanced, have been adapted
and deployed in a real mesh network testbed with off the shelf routers devices
installed with a customized operating system. From this testbed, Open802.11s has
proved to offer better performance than B.A.T.M.A.N-advanced. Following this, a
breakthrough in this work has been the integration of the 802.11s on an Android
mobile device and its subsequent incorporation in the mesh network. This allowed
the study of eventual limitations imposed by the mobile device on the operation of the
mesh network, namely performance and energy scarcity. With this, another major
novelty has followed, by designing, implementing and evaluating several energy
related metrics regarding the battery status of mobile devices. This has enabled the
participation of mobile devices in mesh routing paths in an efficient way.
Our main objective was to implement a mesh network with mobile devices. This has
been achieved and validated through the evaluation of diverse testing scenarios
performed in a real mesh testbed. The obtained results also show that the operation
of a mesh with mobile devices can be enhanced, including the lifetime of mobile
devices, when an energy-aware metric is used.As redes mesh surgem hoje em dia como uma solução de rede em crescimento e
expansão. Neste tipo de redes o comportamento entre os nós é descentralizado e
numa topologia de multihop. Estas características despertam interesse na pesquisa
e desenvolvimento de novas funcionalidades tais como: cooperação entre nós,
distribuição de tarefas, escalabilidade da rede e comunicações mesmo em casos de
uma infraestrutura limitada e o suporte de dispositivos móveis como nós de uma
rede mesh.
Associado à inexistência de um projecto que implemente redes mesh em
dispositivos móveis na camada de ligação de dados (Layer 2), surge a necessidade
de repensar as métricas já existentes com novas informações que façam face às
novas características dos dispositivos móveis, neste caso, os recursos limitados de
bateria.
Por forma a resolver este problema, este trabalho apresenta um estudo detalhado
sobre os projetos, protocolos de routing e métricas desenvolvidas na área das redes
mesh. Além disso, duas soluções que utilizam a camada de ligação de dados,
Open802.11s e BATMAN-advanced, estes foram adaptadao e implementados num
testbed real utilizando routers com um sistema operacional costumizado instalado.
Deste testbed, concluiu-se que o Open802.11s obtem um melhor desempenho que
o BATMAN-advanced. Assim, um dos avanços deste trabalho foi a integração do
Open802.11s num dispositivo móvel Android e sua posterior incorporação na rede
mesh. Isto permitiu o estudo de eventuais limitações impostas pelo dispositivo móvel
ao funcionar numa rede mesh, ou seja, desempenho e a escassez de energia. Com
isso, foi concebida outra novidade, através da concepção, avaliação e
implementação de várias métricas relacionadas com a energia e que têm por base o
estado da bateria do dispositivo. Isto permitiu que os dispositivos móveis participem
na rede mesh e a sua gestão de bateria seja feita de forma eficiente.
O principal objectivo era a implementação de uma rede mesh com dispositivos
móveis. Este foi alcançado e validado através de diversos cenários de teste reais.
Os resultados obtidos demonstram também que o funcionamento de uma rede mesh
com dispositivos móveis pode ser melhorada, incluindo o tempo de vida dos
dispositivos móveis, quando uma métrica que considera a energia é utilizada
System for acquisition, processing and presentation of energy consumption
Tese de mestrado integrado. Engenharia Electrotécnica e de Computadores (Major Telecomunicações). Faculdade de Engenharia. Universidade do Porto. 200
Practical issues of implementing a hybrid multi-NIC wireless mesh-network
Testbeds are a powerful tool to study wireless mesh and sensor networks as
close as possible to real world application scenarios. In contrast to
simulation or analytical approaches these installations face various kinds of
environment parameters. Challenges related to the shared physical medium,
operating system, and used hardware components do arise. In this technical
report about the work-in-progress Distributed Embedded Systems testbed of 100
routers deployed at the Freie Universität Berlin we focis on the software
architecture and give and introduction to the network protocol stack of the
Linux kernel. Furthermore, we discuss our first experiences with a pilot
network setup, the encountered problems and the achieved solutions. This
writing continues our first publication and builds upon the discussed overall
testbed architecture, our experiment methodology, and aspired research
objectives
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