Multicast Routing In MANETS

Numerous system applications require transmitting the same single duplicate of information parcels simultaneously to numerous destinations, it is called multicasting. The Multicast steering has generous impact in MANETs. System use effectiveness is critical for system applications, for example, sound, video-gushing, which are touchy to information conveyance delay. Explores here have been done in the most recent ten years. In this paper, we show a diagram of significant headings in past looks into on cross section and tree based multicast steering convention in MANET. Despite the fact that these conventions perform well under particular portability situations, movement loads, and system conditions, no single convention has been appeared to be ideal in all situations .The essential center is on applications and activity administration, instead of gadget connection. We first audit the applicable parts of system building design and talk about the primary contrasts in the middle of lattice and tree based multicast directing convention, and with a rationale of giving a complete comprehension of these multicast steering conventions and presents the extent of future exploration in this field

Seamless, reliable, video multicast in wireless ad hoc networks

A wireless ad hoc network is a self-organized and dynamically reconfigurable wireless network without central administration and wired infrastructure. Nodes in a wireless ad hoc network can instantly establish a communication structure while each node moves in an arbitrary manner. A wireless ad hoc network is useful for mobile nodes working in a group to accomplish certain tasks. On the other hand, multicast is a very useful and efficient means of supporting group-oriented applications. Multicast is an essential technology for many applications such as video distribution and group video conferencing, data dissemination, disaster relief and battlefield. Video multicasting over wireless ad hoc networks is bandwidth-efficient compared to multiple unicast sessions. However, video multicasting poses great challenges over wireless ad hoc networks. Video packets are both delay and loss sensitive. In addition, due to nodes mobility, the topology of wireless ad hoc networks is frequently changed. As a result, the established links are continuously broken, causing quality loss and interruption in the received video signal. Other challenges include limited battery life of wireless nodes and lower wireless network capacity compared to wired networks. Video multicast over wireless ad hoc networks has been an active area in recent years. The main objective of these studies is to improve the quality of the received video by exploiting the error resilience properties of Multiple Description Coding (MDC) along with multiple paths. In other words, MD video is encoded and transmitted over two different paths to each destination node. If only one path is broken, packets corresponding to the other description on the other path can still arrive at the destination node on time. Layered Coding (LC) and Multiple Description Coding (MDC) have been proposed as video source coding techniques that are robust against inevitable transmission errors. In contrast to MDC, LC encodes a media source into two or more sub-streams, known as layers, one base layer and several enhancement layers. The base layer can be decoded to provide a basic quality of the received video while the enhancement layers are mainly used to refine the quality of the video that is reconstructed from the base layer. If the base layer is corrupted, the enhancement layers become useless, even if they are received correctly. Therefore, the base layer is critically important and is usually highly protected. For MDC, however, these sub-streams are of equal importance in the sense that each sub-stream, also called a description, can be decoded independently to produce a signal of basic quality. When more descriptions are received, the decoder can gradually increase the quality. One main problem of video multicasting for heterogeneous destinations is the assignment of video descriptions and the construction of multicast tree. However, the assignment of MD video and the construction of multicast tree can greatly affect the user satisfaction (i.e., affect the quality of the received video). In this thesis, we introduce novel approaches to improve the user satisfaction for a set of heterogeneous multicast destinations. The main idea of our approaches is to employ the independent-description property of MDC along with multiple multicast trees. However, many questions are raised: How multiple multicast trees should be constructed? And how MD video should be assigned? Is it better to construct multiple multicast trees first and then assign the video descriptions? Or is it better to assign the video descriptions first and we then construct multiple multicast trees? Should we perform that in a distributed manner or in a centralized one? To answer these questions, we propose different algorithms to construct multiple multicast trees and to assign MD video. The proposed algorithms are: Serial MDC, Distributed MDC, and Centralized MDC. Serial MDC constructs multiple paths, to each destination, and assigns a different video description to each of them. After that, it constructs multiple multicast trees. Distributed MDC assigns MD video and constructs multiple multicast trees in parallel and in distributed fashion. In Centralized MDC, the assignment of MD video and the construction of multiple multicast trees are performed in a centralized manner. However, Centralized MDC first constructs multiple multicast trees and then assigns different video description to each multicast tree. We evaluate and compare our proposed algorithms Under different network conditions. For example, Network size, and multicast group size. Simulation results demonstrate that, indeed, the way of multicast trees construction and the assignment of MD video can greatly affect the user satisfaction. In addition, simulation results show that MDC can achieve higher user satisfaction compared to LC with a small cost in terms of number of pure forwarders nodes, bandwidth utilization, and aggregate tree delay. Furthermore, we use our proposed algorithms to develop different multicast protocols for video multicast over wireless ad hoc networks. Specifically, we propose four protocols, namely, Centralized MDMTR (Multiple Disjoint Multicast Trees Routing), Sequential MDMTR, Distributed MDMTR, and Neighbor-aware MDMTR protocols. These protocols take many issues into consideration, rejoining and joining a multicast group, multicast trees maintenance, and mobility of nodes, for example. We evaluate the performance of our proposed protocols and compare them under different network conditions. For example, multicast group size, and mobility of nodes. Simulation results demonstrate that our protocols perform well compared to other protocols in the literature

An Enhanced Hybrid Key Management Protocol for Secure Multicast in Ad Hoc Networks

Colloque avec actes et comité de lecture. internationale.International audienceAn ad hoc network is a collection of wireless mobile hosts forming a temporary network without the aid of any established infrastructure or centralized administration. This exibility in space and time induces new challenges towards the security infrastructure needed to support secure unicast and multicast communications. Especially, traditional group key management architectures meant for wired networks are not appropriate in such environment due to high dynamics and mobility of nodes. In this paper, we propose an enhanced hybrid key management protocol for secure multicast dedicated to operate in ad hoc networks. Built on a protocol called BAAL dedicated to key distribution in wired networks, our approach integrates threshold cryptography and the services of the AKMP protocol to deliver fast, efficient and mobility aware key distribution in a multicast service

RoMR: Robust Multicast Routing in Mobile Ad-Hoc Networks

Support for multicast services is crucial for mobile ad-hoc networks (MANETs) to become a viable alternative to infrastructured networks. Efficient multicasting in MANETs faces challenges not encountered in other types of networks such as the mobility of nodes, the tenuous status of communication links, limited resources, and indefinite knowledge of the network topology. This thesis addresses these challenges by providing a framework and architecture with proactive and reactive components to support multicasting in MANETs emphasizing reliability and efficiency of end-to-end packet delivery. The architecture includes the Robust Multicast Routing protocol (RoMR) to provide multicast services to multicast applications. RoMR's proactive component calculates multiple multicast trees based on the prediction of future availability of the links and the assumption that the trees will become disconnected over time. The reactive components respond to changes in the network topology due to the mobility of the nodes and to changes in the multicast group's membership. Sending redundant data packets over multiple paths further enhances the reliability at the cost of an increase in the use of network resources. RoMR uses approximations to Steiner trees during tree formation and forward error correction encoding techniques during packet transmission in order to counteract this increase. To avoid additional network traffic, trees are distributed only when the existing trees cannot be easily patched to accommodate changes in topology or group membership. The novelty of the proposed protocol stems from integrating techniques that have not previously been combined into a multicasting protocol and a unique method to calculate the relative weights of the links. In addition to the specifications of the protocol, a simulation framework was developed to test different implementations of the various components of RoMR. Simulations compared the performance of the basic version of RoMR to a version that ignored link weights, and to a link-state multicast protocol currently being considered by the Internet Engineering Task Force. A statistical analysis of the results showed that RoMR performed better overall, than the other two protocols

Avaliação de desempenho e mobilidade em redes auto-organizadas

Mestrado em Engenharia de Computadores e TelemáticaAs redes móveis ad hoc (ou auto-organizadas) são um assunto que nos últimos anos tem ganho muita atenção da comunidade científica. Os problemas associados a este tipo de redes foram amplamente estudados e expostos, foram propostas soluções, e algumas até foram tornadas um padrão da indústria. No entanto, a grande maioria do trabalho realizado, é dedicado a resolver só um problema de cada vez. Da mesma forma, as soluções que são testadas por forma a verificar a sua validade, muitas das vezes, são testadas recorrendo a trabalho de simulação. Uma parte do trabalho que é apresentado nesta dissertação de mestrado, junta uma série de protocolos desenvolvidos para redes ad hoc, os quais providenciam funcionalidades como: auto configuração, encaminhamento unicast e multicast, qualidade de serviço e taxação com incentivos numa única solução integrada que interliga as redes ad hoc a redes infra-estruturadas funcionando como uma extensão das mesmas. O demonstrador criado é avaliado de forma experimental, e os resultados obtidos são apresentados e discutidos. Uma vez que a rede ad hoc está interligada à rede infra-estruturada, num ambiente de quarta geração, é também apresentada uma arquitectura que suporta mobilidade de nós entre redes ad hoc e as redes infra-estuturadas que fazem parte do ambiente heterogéneo, e de este para as redes ad hoc é apresentada. A rede geral onde a rede ad hoc é integrada suporta novas tecnologias e tendências em gestão de mobilidade, tais como o protocolo em desenvolvimento IEEE 802.21 Media Independent Handover e gestão de mobilidade baseada em Domínios de Mobilidade Local. A forma como a rede ad hoc se integra com as tecnologias presentes na rede infra-estruturada, e como as especificidades da rede ad hoc são escondidas, é descrita e explicada. ABSTRACT: Mobile Ad hoc network is a subject that has gained lots of attention from the research community in recent years. The problems inherent to this types of networks have been studied and exposed, solutions have been created and even standardized. However, the vast majority of the work performed is dedicated to only one problem at the time. In addition, the tests performed to validate the produced solutions are, most of the times, obtained through simulation work. The work presented in this thesis gathers together a set of ad hoc protocols, providing functionalities such as auto-configuration, unicast and multicast routing, quality of service and charging and rewarding in one integrated testbed, serving as a stub network in a hotspot scenario. A experimental evaluation is performed, and results are presented and discussed. Additionally, since the network belongs to a hotspot of fourth generation, a architecture that supports mobility of nodes between the ad hoc network and infrastructure networks is presented. The general network that includes ad hoc network integrates and supports the new technologies and tendencies in mobility management, such as the IEEE 802.21 Media Independent Handover and mobility management based on Local Mobility Domains. The way the MANET fully integrates with the infrastructure network, and how the ad hoc networks specific characteristics are hidden, is also presented and explained

Soluções de broadcast para redes 4G

Mestrado em Engenharia Electrónica e de TelecomunicaçõesA primeira difusão de conteúdos video e audio teve um forte impacto no quotidiano da população que assistiu a uma revolução nos modelos de transmissão de informação e de entretenimento. A evolução desde então foi significativa, e já na era digital, encontramo-nos face a uma nova sub-elevação da metodologia e do conceito subjacentes à transmissão de conteudos multimédia. O mundo actual apresenta, contudo, diferentes requisitos, de entre os quais se destacam a procura pela alta definição e mobilidade. A mobilidade tem sido um particular foco de atenção por parte dos operadores que exploram agora modelos para entregar uma vasta gama de serviços que sejam atractivos para os utilizadores. Esta dissertação apresenta um sumário das tecnologias emergentes de broadcast que se distinguem nas várias partes do mundo com a sua particular incidência geográfica, características e cenários de aplicação. É ainda apresentada uma arquitectura 4G abordando assuntos inerentes à mobilidade e qualidade de serviço com particular incidência nos aspectos relacionados com a integração de uma tecnologia de broadcast particular. Para avaliação da arquitectura proposta foram efectuados estudos com base num equipamento de broadcast na sua versão comercial, permitindo desta forma obter uma análise que ilustra o que os operadores podem esperar do estado actual dos dispositivos. Os resultados permitiram retirar ilações sobre o comportamento de um equipamento considerado como um produto final a disponibilizar aos operadores, quando integrado num ambiente 4G com suporte de mobilidade e QoS. Nomeadamente é discutida a sua aplicabildiade tendo em linha de conta as desvantagens introduzidas pelas características inerentes à própria tecnologia.Broadcast of video and audio through analogical television completely changed the paradigm of information and entertainment divulgation. Today, in the “digital era”, the Analogue Switch Off revolution is being held. Manufacturers and operators already show concerns regarding the support of mobility, quality of experience and of service. Delivering competitive High Definition contents and providing solutions for the average “on-the-move” user are two of the most important issues to be dealt by the service providers, which are also within the analysis scope of this work. This dissertation presents an overview on the most relevant broadcast technologies which are assumed to be of relative acceptance in their respective target market. It presents their main characteristics and applicability. 4G architectural concepts are also analyzed, closely dealing with mobility and quality of service provisioning, with particular focus on the seamless integration of broadcast technologies. As a mean to evaluate the feasibility of integrating broadcast technologies with 4G architectures, a performance evaluation study was performed using commercial equipment. In this way a several set of considerations constructed illustrating the features and functionalities which operators can expect or disregard from professional commercial broadcasting devices. Results allow the withdrawing of conclusions concerning the integration of a final broadcasting solution when incorporated within a 4G environment with QoS and mobility support. Its applicability is evaluated having in mind the performance drawbacks introduced by the specific technology, and generalized towards the gathering of more general conclusions which consider the main characteristics of the commercial broadcasting devices

Improving Multicast Communications Over Wireless Mesh Networks

In wireless mesh networks (WMNs) the traditional approach to shortest path tree based multicasting is to cater for the needs of the poorest performingnode i.e. the maximum permitted multicast line rate is limited to the lowest line rate used by the individual Child nodes on a branch. In general, this meansfixing the line rate to its minimum value and fixing the transmit power to its maximum permitted value. This simplistic approach of applying a single multicast rate for all nodes in the multicast group results in a sub-optimal trade-off between the mean network throughput and coverage area that does not allow for high bandwidth multimedia applications to be supported. By relaxing this constraint and allowing multiple line rates to be used, the mean network throughput can be improved. This thesis presents two methods that aim to increase the mean network throughput through the use of multiple line rates by the forwarding nodes. This is achieved by identifying the Child nodes responsible for reducing the multicast group rate. The first method identifies specific locations for the placement of relay nodes which allows for higher multicast branch line rates to be used. The second method uses a power control algorithm to tune the transmit power to allow for higher multicast branch line rates. The use of power control also helps to reduce the interference caused to neighbouring nodes.Through extensive computer simulation it can be shown that these two methods can lead to a four-fold gain in the mean network throughput undertypical WMN operating conditions compared with the single line rate case

Authentication and key establishment in wireless networks

Ph.DDOCTOR OF PHILOSOPH