Página 1 dos resultados de 4615 itens digitais encontrados em 0.004 segundos

Research challenges in QoS routing

Masip-Bruin, X.; Yannuzzi, M.; Domingo-Pascual, J.; Fonte, A.; Curado, M.; Monteiro, E.; Kuipers, F.; Van Mieghem, P.; Avallone, S.; Ventre, G.; Aranda-Gutiérrez, P.; Hollick, M.; Steinmetz, R.; Iannone, L.; Salamatian, K.
Fonte: Universidade de Coimbra Publicador: Universidade de Coimbra
Tipo: Artigo de Revista Científica Formato: aplication/PDF
Português
Relevância na Pesquisa
37.118237%
Quality of Service Routing is at present an active and remarkable research area, since most emerging network services require specialized Quality of Service (QoS) functionalities that cannot be provided by the current QoS-unaware routing protocols. The provisioning of QoS based network services is in general terms an extremely complex problem, and a significant part of this complexity lies in the routing layer. Indeed, the problem of QoS Routing with multiple additive constraints is known to be NP-hard. Thus, a successful and wide deployment of the most novel network services demands that we thoroughly understand the essence of QoS Routing dynamics, and also that the proposed solutions to this complex problem should be indeed feasible and affordable. This article surveys the most important open issues in terms of QoS Routing, and also briefly presents some of the most compelling proposals and ongoing research efforts done both inside and outside the E-Next Community to address some of those issues.; http://www.sciencedirect.com/science/article/B6TYP-4GKWC1Y-5/1/200480404f452f53c905bb40545fa337

Scatter Search para problemas de roterização de veículos com frota heterogênea, janelas de tempo e entregas fracionadas.; Scatter search for Heterogeneous Fleet vehicle routing problem with Time Windows and Split Deliveries.

Belfiore, Patrícia Prado
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 03/03/2006 Português
Relevância na Pesquisa
37.150786%
Esta tese estuda a implementação de heurísticas e da metaheurística scatter search (SS) em um problema de roteirização de veículos com frota heterogênea, janelas de tempo e entregas fracionadas (Heterogeneous Fleet Vehicle Routing Problem with Time Windows and Split Deliveries – HFVRPTWSD). O HFVRPTWSD é uma combinação do problema de roteirização com frota heterogênea (HFVRP), problema de roteirização de veículos com janelas de tempo (VRPTW) e problema de roteirização com entregas fracionadas (VRPSD). O problema é baseado em um único depósito, a demanda dos clientes pode ser maior que a capacidade dos veículos e, além das restrições de janelas de tempo, há também restrições de capacidade dos veículos e restrições quanto ao tipo de veículo. O VRPSD foi introduzido na literatura por Dror e Trudeau em 1989. No problema de roteirização de veículos com entregas fracionadas, cada cliente pode ser abastecido por mais de um veículo, enquanto no problema clássico de roteirização de veículos (VRP), cada cliente é atendido por um único veículo. Desta forma, para o VRPSD, além dos roteiros de entrega, deve-se determinar a quantidade entregue a cada cliente em cada veículo. Todos os problemas de roteirização com entregas fracionadas encontrados na literatura (VRPSD e suas extensões) têm como característica frota homogênea. O problema estudado neste trabalho difere...

Formulação algébrica para a modelagem de algoritmos de roteamento multi-restritivo hop-by-hop.; Algebraic formulation for modeling hop-by-hop multi-constrained routing algorithms.

Herman, Walmara de Paula
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 04/04/2008 Português
Relevância na Pesquisa
37.118237%
Este trabalho apresenta uma nova estrutura matemática para a álgebra de caminhos, que permite analisar a convergência dos algoritmos de roteamento multi-restritivos hop-by-hop e, sob o ponto de vista da engenharia de tráfego e da Qualidade de Serviço (QoS) na arquitetura Generalized Multiprotocol Label Switching (GMPLS), garantir de maneira confiável a incorporação de novas métricas de roteamento aos algoritmos de roteamento baseados em múltiplas restrições. Baseando-se nessa nova álgebra de caminhos, são analisadas as propriedades de monotonicidade, isotonicidade e liberdade, conhecidas por garantir a convergência dos algoritmos de roteamento e, ao contrário do indicado na literatura até o momento, verifica-se que a propriedade de monotonicidade não e condição necessária e nem suficiente para garantir a convergência dos algoritmos de roteamento multi-restritivos hop-by-hop. Sendo assim, este trabalho propõe uma nova propriedade, denominada coerência, para a garantia da convergência do roteamento hop-by-hop e um novo algoritmo de roteamento hop-by-hop com convergência garantida. Para avaliar os resultados teóricos obtidos, s~ao analisados dois estudos de casos de aplicação do roteamento multi-restritivos hop-by-hop com o uso de uma ferramenta de simulação desenvolvida em MATLAB e baseada no algoritmo Eliminação de Loop pelo Nó de Destino (ELND) também proposto. Como resultado das simulações desses estudos de casos...

Roteamento de circuitos VLSI; Routing VLSI circuits

Leonhardt, Charles Capella
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Trabalho de Conclusão de Curso Formato: application/pdf
Português
Relevância na Pesquisa
37.118237%
Roteamento é a etapa do fluxo de geração de circuitos integrados onde são realizadas as interconexões entre os diferentes elementos do circuito. Está incluído na etapa de síntese física, que trata da construção do leiaute, uma informação geométrica na qual são representados os transistores e suas interconexões. O roteamento assume grande importância devido à crescente influência das interconexões no atraso total do circuito e o acréscimo de área que um circuito de difícil roteamento pode gerar. Além disto, o tempo de execução costuma ser um fator limitante que impede que algoritmos que possibilitem maiores otimizações sejam usados. Diante disto, este trabalho tem como objetivo o desenvolvimento de uma ferramenta para roteamento global e detalhado de circuitos integrados, que seja capaz de rotear circuitos com grande número de elementos com um bom compromisso entre qualidade de roteamento e tempo de execução. Outro objetivo é desenvolver uma ferramenta para roteamento intracell utilizada na geração de bibliotecas de células. Para atingir os objetivos propostos foi necessário desenvolver soluções adequadas a cada uma das etapas do fluxo de roteamento. O algoritmo para roteamento intracell incluindo uma fase de otimização obtém ganho de 0...

Roteamento global de circuitos VLSI; Global routing for VLSI circuits

Reimann, Tiago Jose
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Dissertação Formato: application/pdf
Português
Relevância na Pesquisa
37.097607%
Este trabalho apresenta a implementação de um roteador global de circuitos integrados capaz de tratar os problemas de roteamento atuais, utilizando como referência para avaliação os circuitos de benchmark publicados durante as competições de roteamento global realizadas no ACM International Symposium on Physical Design 2007 e 2008. O roteador global desenvolvido utiliza como ferramenta principal a técnica de ripup and reroute associada às técnicas de roteamento monotônico e maze routing, ambas com grande histórico de uso nas ferramentas acadêmicas descritas também neste trabalho. O desenvolvimento da ferramenta também possui características diferenciadas e únicas, com um novo método de ordenamento das redes durante a fase de rip-up and reroute. Para a geração dos resultados foram definidas duas versões diferentes da ferramenta, sendo estas duas versões analisadas com duas diferentes técnicas de construção das árvores de roteamento, gerando no total quatro configurações da ferramenta. Como decisão de projeto, a versão principal utilizada no desenvolvimento e discussão dos resultados é a versão que prioriza a qualidade do roteamento, utilizando MSTs para construção das árvores de roteamento. Os resultados mostram que o roteador global desenvolvido é capaz de gerar resultados com boa qualidade mesmo sem fazer uso de técnicas de identificação de áreas de congestionamento...

Scale-free networks and scalable interdomain routing

Rodrigues, Pedro Miguel Fonseca
Fonte: Faculdade de Ciências e Tecnologia Publicador: Faculdade de Ciências e Tecnologia
Tipo: Dissertação de Mestrado
Publicado em //2010 Português
Relevância na Pesquisa
37.163848%
Trabalho apresentado no âmbito do Mestrado em Engenharia Informática, como requisito parcial para obtenção do grau de Mestre em Engenharia Informática; The exponential growth of the Internet, due to its tremendous success, has brought to light some limitations of the current design at the routing and arquitectural level, such as scalability and convergence as well as the lack of support for traffic engineering, mobility, route differentiation and security. Some of these issues arise from the design of the current architecture, while others are caused by the interdomain routing scheme - BGP. Since it would be quite difficult to add support for the aforementioned issues, both in the interdomain architecture and in the in the routing scheme, various researchers believe that a solution can only achieved via a new architecture and (possibly) a new routing scheme. A new routing strategy has emerged from the studies regarding large-scale networks, which is suitable for a special type of large-scale networks which characteristics are independent of network size: scale-free networks. Using the greedy routing strategy a node routes a message to a given destination using only the information regarding the destination and its neighbours...

Multipath inter-domain policy routing

Amaral, Pedro Miguel Figueiredo
Fonte: Faculdade de Ciências e Tecnologia Publicador: Faculdade de Ciências e Tecnologia
Tipo: Tese de Doutorado
Publicado em //2012 Português
Relevância na Pesquisa
37.135745%
Dissertação submetida para a obtenção do grau de Doutor em Engenharia Electrotécnica e de Computadores; Routing can be abstracted to be a path nding problem in a graph that models the network. The problem can be modelled using an algebraic approach that describes the way routes are calculated and ranked. The shortest path problem is the most common form and consists in nding the path with the smallest cost. The inter-domain scenario introduces some new challenges to the routing problem: the routing is performed between independently con gured and managed networks; the ranking of the paths is not based on measurable metrics but on policies; and the forwarding is destination based hop-by-hop. In this thesis we departed from the Border gateway Protocol (BGP) identifying its main problems and elaborating on some ideal characteristics for a routing protocol suited for the inter-domain reality. The main areas and contributions of this work are the following: The current state of the art in algebraic modeling of routing problems is used to provide a list of possible alternative conditions for the correct operation of such protocols. For each condition the consequences in terms of optimality and network restrictions are presented. A routing architecture for the inter-domain scenario is presented. It is proven that it achieves a multipath routing solution in nite time without causing forwarding loops. We discuss its advantages and weaknesses. A tra c-engineering scheme is designed to take advantage of the proposed architecture. It works using only local information and cooperation of remote ASes to minimize congestion in the network with minimal signalling. Finally a general model of a routing protocol based on hierarchical policies is used to study how e cient is the protocol operation when the correctness conditions are met. This results in some conclusions on how the policies should be chosen and applied in order to achieve speci c goals.

Planning and verification of multipath routing protocols

Vitorino, Tiago Miguel Mendes Ferreira
Fonte: Universidade Nova de Lisboa Publicador: Universidade Nova de Lisboa
Tipo: Dissertação de Mestrado
Publicado em /09/2014 Português
Relevância na Pesquisa
37.097607%
Conventionally the problem of the best path in a network refers to the shortest path problem. However, for the vast majority of networks present nowadays this solution has some limitations which directly affect their proper functioning, as well as an inefficient use of their potentialities. Problems at the level of large networks where graphs of high complexity are commonly present as well as the appearing of new services and their respective requirements, are intrinsically related to the inability of this solution. In order to overcome the needs present in these networks, a new approach to the problem of the best path must be explored. One solution that has aroused more interest in the scientific community considers the use of multiple paths between two network nodes, where they can all now be considered as the best path between those nodes. Therefore, the routing will be discontinued only by minimizing one metric, where only one path between nodes is chosen, and shall be made by the selection of one of many paths, thereby allowing the use of a greater diversity of the present paths (obviously, if the network consents). The establishment of multi-path routing in a given network has several advantages for its operation. Its use may well improve the distribution of network traffic...

An Energy-aware multipath routing extension for heterogeneous Ad hoc networks

Lima Junior, Josias Barbosa de; Kelner, Judith orientadora)
Fonte: Universidade Federal de Pernambuco Publicador: Universidade Federal de Pernambuco
Tipo: Dissertação
Português
Relevância na Pesquisa
37.118237%
Recentemente, novas técnicas de comunicação surgiram que usam tecnologia sem fio e são capazes de se autoconfigurar. A combinação desses fatores elimina a necessidade de utilizar estruturas cabeadas e configurações pré-definidas. Neste trabalho, o autor desenvolve uma versão simulada, através do simulador de rede “network Simulator 3” (ns-3), do arcabouço “Heterogeneous Technologies Routing” (HTR), que se propõe à interconectar dispositivos em redes heterogêneas ad hoc, estendendo o seu suporte às tecnologias heterogêneas com a adição de dispositivos WiMAX e LTE, propõe uma extensão para fornecer um roteamento baseado em múltiplos caminhos (“Multipath”) e investiga o impacto de modificar os parâmetros de configuração do roteamento no tempo de convergência da rede e consumo de energia. Apesar de um grande número de obras existentes que investigam o impacto da mudança de parâmetros de configuração do roteamento, no meu conhecimento, nenhum deles investiga o impacto destes no tempo de convergência do protocolo e consumo de energia. O “Multipath HTR”, a extensão proposta, oferece vários benefícios como balanceamento de carga, tolerância a falhas, prevenção de “loops” de roteamento...

Algoritmo de roteamento Anycast baseado em algoritmos genéticos para redes tolerantes a atrasos e desconexões; Anycast routing algorithm based on genetic algorithms for delay and disruption tolerant networks

Silva, Éderson Rosa da
Fonte: Universidade Federal de Uberlândia Publicador: Universidade Federal de Uberlândia
Tipo: Tese de Doutorado
Português
Relevância na Pesquisa
37.118237%
As redes tolerantes a atrasos e desconexões ou DTNs (Delay and Disruption Tolerant Networks) possuem o potencial de conectar dispositivos e áreas do mundo que não são servidas por redes tradicionais. O desenvolvimento dessas redes permite levar a revolução da informação tecnológica às populações dos países em desenvolvimento carentes de infraestrutura, especialmente nas regiões remotas e rurais. Neste cenário, as DTNs contribuem oferecendo uma arquitetura alternativa de redes de baixo custo, tolerante a enlaces intermitentes com atrasos variáveis e, possivelmente, longos. Um dos principais desafios que surge no projeto de redes com essas características é o roteamento, sendo este um tópico de grande interesse e importância na área das DTNs. Atualmente, a arquitetura DTN especificada pelo grupo de pesquisa DTNRG (DTN Research Group) oferece uma framework na qual uma variedade de protocolos de roteamento podem ser utilizados, mas não define nenhum protocolo de roteamento particular. Além disso, os nós DTN, provavelmente, terão que suportar diferentes estratégias de roteamento, a fim de operar eficientemente na enorme diversidade de ambientes em que o nó pode se encontrar. Assim, neste trabalho é proposto um algoritmo de roteamento para DTNs em cenários onde a topologia da rede pode ser conhecida ao longo do tempo. Mais precisamente...

Tactical Vehicle Routing Planning with Application to Milk Collection and Distribution

Dayarian, Iman
Fonte: Université de Montréal Publicador: Université de Montréal
Tipo: Thèse ou Mémoire numérique / Electronic Thesis or Dissertation
Português
Relevância na Pesquisa
37.118237%
De nombreux problèmes pratiques qui se posent dans dans le domaine de la logistique, peuvent être modélisés comme des problèmes de tournées de véhicules. De façon générale, cette famille de problèmes implique la conception de routes, débutant et se terminant à un dépôt, qui sont utilisées pour distribuer des biens à un nombre de clients géographiquement dispersé dans un contexte où les coûts associés aux routes sont minimisés. Selon le type de problème, un ou plusieurs dépôts peuvent-être présents. Les problèmes de tournées de véhicules sont parmi les problèmes combinatoires les plus difficiles à résoudre. Dans cette thèse, nous étudions un problème d’optimisation combinatoire, appartenant aux classes des problèmes de tournées de véhicules, qui est liée au contexte des réseaux de transport. Nous introduisons un nouveau problème qui est principalement inspiré des activités de collecte de lait des fermes de production, et de la redistribution du produit collecté aux usines de transformation, pour la province de Québec. Deux variantes de ce problème sont considérées. La première, vise la conception d’un plan tactique de routage pour le problème de la collecte-redistribution de lait sur un horizon donné...

Random walk routing for wireless sensor networks with regular topologies

Tian, H.; Shen, H.; Matsuzawa, T.
Fonte: Springer New York LLC Publicador: Springer New York LLC
Tipo: Artigo de Revista Científica
Publicado em //2006 Português
Relevância na Pesquisa
37.118237%
Topology is one of the most important characteristics for any type of networks because it represents the network’s inherent properties and has great impact on the performance of the network. For wireless sensor networks (WSN), a well-deployed regular topology can help save more energy than what a random topology can do. WSNs with regular topologies can prolong network lifetime as studied in many previous work. However, little work has been done in developing effective routing algorithms for WSNs with regular topologies, except routing along a shortest path with the knowledge of global location information of sensor nodes. In this paper, a new routing protocol based on random walk is proposed. It does not require global location information. It also achieves load balancing property inherently for WSNs which is difficult to achieve by other routing protocols. In the scenarios where the message required to be sent to the base station is in comparatively small size with the inquiry message among neighboring nodes, it is proved that the random walk routing protocol can guarantee high probability of successful transmission from the source to the base station with the same amount of energy consumption as the shortest path routing. Since in many applications of WSNs...

Design study of energy-efficient routing protocol for wireless sensor networks.

Lu, Lifang
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2009 Português
Relevância na Pesquisa
37.097607%
Recent advances in wireless sensor networks have led to an emergence of many routing protocols. Limited battery capacity of sensor nodes makes energy efficiency a major and challenge problem in wireless sensor networks. Thus, the routing protocols for wireless sensor networks must be energy efficient in order to maximise the network lifetime. In this thesis, we developed a centralised clustering, energy-efficient routing protocol for wireless sensor networks. Our protocol consists of a cluster head selection algorithm, a cluster formation scheme and a routing algorithm for the data transmission between cluster heads and the base station. The cluster head selection algorithm is performed by the base station using global information of the network. This algorithm aiming at choosing cluster heads that ensure both the intra-cluster data transmission and inter-cluster data transmission are energy-efficient. The cluster formation scheme is accomplished by exchanging messages between non-cluster-head nodes and the cluster head to ensure a balanced energy load among cluster heads. The routing algorithm is based on the optimal transmission range for the data transmission between cluster heads and the base station using multi-hop. The performance of our routing protocol is evaluated by comparing with three existing routing protocols on a simulation platform. The simulation results show that our protocol can achieve better performance in terms of energy efficiency and network lifetime. Because of the centralised algorithm and multi-hop routing...

Energy-efficient beaconless geographic routing in wireless sensor networks

Zhang, H.; Shen, H.
Fonte: IEEE Computer Soc Publicador: IEEE Computer Soc
Tipo: Artigo de Revista Científica
Publicado em //2010 Português
Relevância na Pesquisa
37.118237%
Geographic routing is an attractive localized routing scheme for wireless sensor networks (WSNs) due to its desirable scalability and efficiency. Maintaining neighborhood information for packet forwarding can achieve a high efficiency in geographic routing, but may not be appropriate for WSNs in highly dynamic scenarios where network topology changes frequently due to nodes mobility and availability. We propose a novel online routing scheme, called Energy-efficient Beaconless Geographic Routing (EBGR), which can provide loop-free, fully stateless, energy-efficient sensor-to-sink routing at a low communication overhead without the help of prior neighborhood knowledge. In EBGR, each node first calculates its ideal next-hop relay position on the straight line toward the sink based on the energy-optimal forwarding distance, and each forwarder selects the neighbor closest to its ideal next-hop relay position as the next-hop relay using the Request-To-Send/Clear-To-Send (RTS/CTS) handshaking mechanism. We establish the lower and upper bounds on hop count and the upper bound on energy consumption under EBGR for sensor-to-sink routing, assuming no packet loss and no failures in greedy forwarding. Moreover, we demonstrate that the expected total energy consumption along a route toward the sink under EBGR approaches to the lower bound with the increase of node deployment density. We also extend EBGR to lossy sensor networks to provide energy-efficient routing in the presence of unreliable communication links. Simulation results show that our scheme significantly outperforms existing protocols in wireless sensor networks with highly dynamic network topologies.; Haibo Zhang and Hong Shen

Performance analysis of mobile ad hoc networking routing protocols

Thong, Lee Kok
Fonte: Monterey, California. Naval Postgraduate School Publicador: Monterey, California. Naval Postgraduate School
Tipo: Tese de Doutorado Formato: xviii, 133 p.
Português
Relevância na Pesquisa
37.175295%
Approved for public release, distribution is unlimited; This thesis presents a simulation and performance evaluation analysis of the various routing protocols that have been proposed for the Mobile Ad Hoc Network (MANET) environment using the Network Simulator-2 (NS-2) tool. Many routing protocols have been proposed by the academic communities for possible practical implementation of a MANET in military, governmental and commercial environments. Four (4) such routing protocols were chosen for analysis and evaluation: Ad Hoc On-demand Distance Vector routing (AODV), Dynamic Source Routing (DSR), Destination-Sequenced Distance Vector routing (DSDV) and Optimized Link State Routing (OLSR). NS-2 is developed and maintained by the University of Southern California's Information Sciences Institute (ISI). Leveraging on NS-2's simulation capabilities, the key performance indicators of the routing protocols were analyzed such as data network throughput, routing overhead generation, data delivery delay as well as energy efficiency or optimization. The last metric is explored, especially due to its relevance to the mobile environment. Energy is a scare commodity in a mobile ad hoc environment. Any routing software that attempts to minimize energy usage will prolong the livelihood of the devices used in the battlefield. Three important mobility models are considered...

A general approach for all-to-all routing in multihop WDM optical networks

Liang, Weifa; Shen, Xiaojun
Fonte: Institute of Electrical and Electronics Engineers (IEEE Inc) Publicador: Institute of Electrical and Electronics Engineers (IEEE Inc)
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
37.118237%
WDM optical networks provide unprecedented high speed and reliability for message transfer among the nodes. All-to-all routing is a fundamental routing problem in such networks and has been well studied on single hop WDM networks. However, the number of w

Multipath Fault-tolerant Routing Policies to deal with Dynamic Link Failures in High Speed Interconnection Networks

Zarza, Gonzalo Alberto
Fonte: [Barcelona] : Universitat Autònoma de Barcelona, Publicador: [Barcelona] : Universitat Autònoma de Barcelona,
Tipo: Tesis i dissertacions electròniques; info:eu-repo/semantics/doctoralThesis; info:eu-repo/semantics/publishedVersion Formato: application/pdf
Publicado em //2011 Português
Relevância na Pesquisa
37.097607%
Les xarxes d'interconnexió tenen com un dels seus objectius principals comunicar i enllaçar els nodes de processament dels sistemes de còmput d'altes prestacions. En aquest context, les fallades de xarxa tenen un impacte considerablement alt, ja que la majoria dels algorismes d'encaminament no van ser dissenyats per tolerar aquestes anomalies. A causa d'això, fins i tot una única fallada d'enllaç té la capacitat d'embussar missatges a la xarxa, provocant situacions de bloqueig o, encara pitjor, és capaç d'impedir la correcta finalització de les aplicacions que es trobin en execució en el sistema de còmput. En aquesta tesi presentem polítiques d'encaminament tolerants a fallades basades en els conceptes d'adaptabilitat i evitació de bloquejos, dissenyades per a xarxes afectades per un gran nombre de fallades d'enllaços. Es presenten dues contribucions al llarg de la tesi, a saber: un mètode d'encaminament tolerant a fallades multicamí, i una tècnica nova i escalable d'evitació de bloquejos. La primera de les contribucions de la tesi és un algorisme d'encaminament adaptatiu multicamí, anomenat Fault-tolerant Distributed Routing Balancing (FT-DRB), que permet explotar la redundància de camins de comunicació de les topologies de xarxa actuals...

Performance comparison between Ad Hoc On Demand Distance Vector and Dynamic Source Routing Protocols with security encryption using OPNET

Jafferi, Jaseem
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Tese de Doutorado
Português
Relevância na Pesquisa
37.118237%
Application for wireless networking has been evolving rapidly and is becoming an integral part in our everyday life. Also with the recent performance advancement in wireless communication technologies, mobile wireless ad-hoc networks has been used in many areas such as military, health and commercial applications. Mobile ad hoc networks utilize radio waves and microwaves to maintain communication channel between computers. 802.11 (Wi-Fi) is the pre-eminent technology for building general purpose wireless networks. Mobile ad-hoc networking (MANET) utilize the Internet Protocol (IP) suite and aims at supporting robust and efficient operation by incorporating routing functionality into the mobile nodes. MANET is among one of the wireless networks that uses 802.11 to transmit data from the source to the destination. Since MANET is used in applications like defense, security is of vital importance due to its wireless nature. Wireless networks are vulnerable to attacks like eavesdropping, Man-In-The-Middle-Attack (MITM), hijacking, and so are MANETs. A malicious node can get within the wireless range of the nodes in the MANET and can disrupt the communication process. Various routing protocols have been proposed using encryption techniques to protect routing in MANETs. In this thesis...

Stochastic analysis of ant-based routing and probabilistic modeling of medium access control in wireless networks

Fang, Rui
Fonte: University of Delaware Publicador: University of Delaware
Tipo: Tese de Doutorado
Português
Relevância na Pesquisa
37.150786%
Rossi, Louis F.; In computer networks, routing determines how data move across a network from a source to a destination, while medium access control (MAC) defines when and how to transmit data from one node to another.Ant-based routing protocols have successfully provided an effective, if not optimal, solution to the routing problem by using control packets, called "ants", to explore networks, discover routes and reinforce the best routes. However, the modeling of ant-based routing in the context of wireless local area networks (WLANs) is challenged by the intrinsic complexity of wireless medium access control and its cross-layer interaction. Therefore, this dissertation mainly concerns two problems: improvement of an ant-based algorithm's performance on routing problem and mathematical characterization of medium access control for wireless local area networks. Our contributions are threefold. First we introduce a novel strategy for ant-based routing to achieve optimal solutions that have least hop count. Next, we modestly analyze the integrated behaviors of ant-based routing with medium access control based on the case investigations of a practical MAC protocol MACA (Multiple Access with Collision Avoidance). Finally, we develop a detailed Markov model according to the comprehensive descriptions of the Distributed Coordination Functions (DCF) in IEEE 802.11...

A Reactive Location Routing Algorithm with Cluster-Based Flooding for Inter-Vehicle Communication

Aquino S,Raúl; B,Arthur Edwards
Fonte: Centro de Investigación en computación, IPN Publicador: Centro de Investigación en computación, IPN
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2006 Português
Relevância na Pesquisa
37.118237%
In this paper, we present a reactive location routing algorithm with cluster-based flooding for inter-vehicle communication. We consider a motorway environment with associated high mobility and compare position-based and non-position-based routing strategies, along with a limiting function for flooding mechanisms in reactive ad-hoc protocols. The performance of Dynamic Source Routing (DSR) and Ad-Hoc On-demand Distance Vector Routing (AODV) for non-positional and Location Routing Algorithm with Cluster-Based Flooding (LORA_CBF) for positional algorithms is considered. First, for small-scale networks, our research validates our proposed simulation model with the results of a test bed and the results of mathematical analysis. Then, for large-scale networks, we use simulations to compare our model with both the AODV and DSR reactive routing algorithms. Finally, we use a microscopic traffic model, developed in OPNET, to ascertain the mobility of 250 vehicles on a motorway with regards to average Route Discovery (RD) time, End-to-End Delay (EED), Routing Load, Routing Overhead, Overhead, and Delivery Ratio.