Experimental evaluation of the usage of ad hoc networks as stubs for multiservice networks

This paper describes an experimental evaluation of a multiservice ad hoc network, aimed to be interconnected with an infrastructure, operator-managed network. This network supports the efficient delivery of services, unicast and multicast, legacy and multimedia, to users connected in the ad hoc network. It contains the following functionalities: routing and delivery of unicast and multicast services; distributed QoS mechanisms to support service differentiation and resource control responsive to node mobility; security, charging, and rewarding mechanisms to ensure the correct behaviour of the users in the ad hoc network. This paper experimentally evaluates the performance of multiple mechanisms, and the influence and performance penalty introduced in the network, with the incremental inclusion of new functionalities. The performance results obtained in the different real scenarios may question the real usage of ad-hoc networks for more than a minimal number of hops with such a large number of functionalities deployed

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

A Secure Group Communication Architecture for a Swarm of Autonomous Unmanned Aerial Vehicles

This thesis investigates the application of a secure group communication architecture to a swarm of autonomous unmanned aerial vehicles (UAVs). A multicast secure group communication architecture for the low earth orbit (LEO) satellite environment is evaluated to determine if it can be effectively adapted to a swarm of UAVs and provide secure, scalable, and efficient communications. The performance of the proposed security architecture is evaluated with two other commonly used architectures using a discrete event computer simulation developed using MatLab. Performance is evaluated in terms of the scalability and efficiency of the group key distribution and management scheme when the swarm size, swarm mobility, multicast group join and departure rates are varied. The metrics include the total keys distributed over the simulation period, the average number of times an individual UAV must rekey, the average bandwidth used to rekey the swarm, and the average percentage of battery consumed by a UAV to rekey over the simulation period. The proposed security architecture can successfully be applied to a swarm of autonomous UAVs using current technology. The proposed architecture is more efficient and scalable than the other tested and commonly-used architectures. Over all the tested configurations, the proposed architecture distributes 55.2 – 94.8% fewer keys, rekeys 59.0 - 94.9% less often per UAV, uses 55.2 - 87.9% less bandwidth to rekey, and reduces the battery consumption by 16.9 – 85.4%

A Secure and Efficient Communications Architecture for Global Information Grid Users via Cooperating Space Assets

With the Information Age in full and rapid development, users expect to have global, seamless, ubiquitous, secure, and efficient communications capable of providing access to real-time applications and collaboration. The United States Department of Defense’s (DoD) Network-Centric Enterprise Services initiative, along with the notion of pushing the “power to the edge,” aims to provide end-users with maximum situational awareness, a comprehensive view of the battlespace, all within a secure networking environment. Building from previous AFIT research efforts, this research developed a novel security framework architecture to address the lack of efficient and scalable secure multicasting in the low earth orbit satellite network environment. This security framework architecture combines several key aspects of different secure group communications architectures in a new way that increases efficiency and scalability, while maintaining the overall system security level. By implementing this security architecture in a deployed environment with heterogeneous communications users, reduced re-keying frequency will result. Less frequent re-keying means more resources are available for throughput as compared to security overhead. This translates to more transparency to the end user; it will seem as if they have a “larger pipe” for their network links. As a proof of concept, this research developed and analyzed multiple mobile communication environment scenarios to demonstrate the superior re-keying advantage offered by the novel “Hubenko Security Framework Architecture” over traditional and clustered multicast security architectures. For example, in the scenario containing a heterogeneous mix of user types (Stationary, Ground, Sea, and Air), the Hubenko Architecture achieved a minimum ten-fold reduction in total keys distributed as compared to other known architectures. Another experiment demonstrated the Hubenko Architecture operated at 6% capacity while the other architectures operated at 98% capacity. In the 80% overall mobility experiment with 40% Air users, the other architectures re-keying increased 900% over the Stationary case, whereas the Hubenko Architecture only increased 65%. This new architecture is extensible to numerous secure group communications environments beyond the low earth orbit satellite network environment, including unmanned aerial vehicle swarms, wireless sensor networks, and mobile ad hoc networks

Optimização de recursos para difusão em redes de próxima geração

Doutoramento em ElectrotecniaEsta tese aborda o problema de optimização de recursos de rede, na entrega de Serviços de Comunicação em Grupo, em Redes de Próxima Geração que suportem tecnologias de difusão. De acordo com esta problemática, são feitas propostas que levam em atenção a evolução espectável das redes 3G em Redes Heterogéneas de Próxima Geração que incluam tecnologias de difusão tais como o DVB. A optimização de recursos em Comunicações em Grupo é apresentada como um desafio vertical que deve cruzar diversas camadas. As optimizações aqui propostas cobrem tanto a interface entre Aplicação e a Plataforma de Serviços para a disponibilização de serviços de comunicação em grupo, como as abstracções e mapeamentos feitos na interface entre a Rede Central e a Rede de Acesso Rádio. As optimizações propostas nesta tese, assumem que o caminho evolutivo na direcção de uma Rede de Próxima Geração é feito através do IP. Em primeiro lugar são endereçadas as optimizações entre a Aplicação e a Plataforma de Serviços que já podem ser integradas nas redes 3G existentes. Estas optimizações podem potenciar o desenvolvimento de novas e inovadoras aplicações, que através do uso de mecanismos de distribuição em difusão podem fazer um uso mais eficiente dos recursos de rede. De seguida são apresentadas optimizações ao nível da interface entre a Rede Central e a Rede de Acesso Rádio que abordam a heterogeneidade das redes futuras assim como a necessidade de suportar tecnologias de difusão. É ainda considerada a possibilidade de aumentar a qualidade de serviço de serviços de difusão através do mapeamento do IP multicast em portadoras unidireccionais. Por forma a validar todas estas optimizações, vários protótipos foram desenvolvidos com base num router avançado para redes de acesso de próxima geração. As funcionalidades e arquitectura de software desse router são também aqui apresentadas.This thesis addresses the problem of optimizing network resource usage, for the delivery of Group Services, in Next Generation Networks featuring broadcast technologies. In this scope, proposals are made according to the expected evolution of 3G networks into Next Generation Heterogeneous Networks that include broadcast technologies such as DVB. Group Communication resource optimization is considered a vertical challenge that must cross several layers. The optimizations here proposed cover both Application to Service Platform interfaces for group communication services, and Core Network to Radio Access Network interface abstractions and mappings. The proposed optimizations are also presented taking into consideration network evolution path towards an All-IP based Next Generation Network. First it is addressed the Application to Service Platform optimization, which can already be deployed over 3G networks. This optimization could potentiate the development of new and innovative applications that through the use of broadcast/multicast service delivery mechanisms could be more efficient network wise. Next proposals are made on the Core Network to Radio Access Network interfaces that address the heterogeneity of future networks and consider the need to support broadcast networks. It is also considered the possibility to increase the Quality of Service of broadcast/multicast services based on the dynamic mapping of IP multicast into unicast radio bearers. In order to validate these optimizations, several prototypes were built based on an advanced access router for next generation networks. Such access router functionalities and software architecture are also presented here

Desempenho de QoS e mobilidade de sessões multicast em redes dinâmicasMes

Mestrado em Engenharia Electrónica e TelecomunicaçõesThe increasing demand in multimedia group services, contextawareness and seamless mobility implies strict requirements that cannot be satisfactorily addressed by the traditional transport control architectures for session content delivery. Moreover, context-aware networks introduce personalized concepts: any change in context can change the overall services and network environments, requiring the network and multicast sessions to be completely restructured in a very dynamic way. Regarding the complexity of maintaining scalability in context-aware networks, this Thesis has as main goal the development of an intelligent module, included in C-CAST architecture, capable of managing the entire network scheme. This mechanism depending on the scenario and the context of users and sources, and in cooperation with other network entities, must decide the most suitable network transport path in order to provide the best multiparty content delivery to the users, and manage the dynamicity of the network whenever changes occur. To perform its implementation, it was used an approach based in the interaction of different network components, exchanging context information between them. The intelligent module, using the updated network information, decides the better network connection to serve each user. In order to simulate the network behaviour in various situations, several scenarios were tested to evaluate its performance. The network is evaluated according to the several configured parameters, evaluating the improvements achieved in the network performance concerning different metrics, e.g. delay, lost packets ratio, overhead introduced by the architecture signalling. Through the implemented simulation setup, it is possible to conclude that the deployment of the solution proposed effectively provides an enhanced service to the users, distributing the multiparty content with QoS assurance using context information.O aumento da exigência em serviços de grupo, redes baseadas em contexto e mobilidade transparente implicam requisitos rígidos que não podem ser satisfeitos pelas arquitecturas tradicionais de controlo de transporte para entrega de conteúdos de sessão. Não obstante, redes baseadas em contexto introduzem conceitos personalizados: qualquer mudança no contexto pode mudar completamente os serviços e a própria rede, sendo necessário que a rede e as sessões multicast sejam completamente reestruturadas de uma forma dinâmica. Tendo em conta a complexidade de manter a escalabilidade em redes baseadas em contexto, esta Tese tem como principal objectivo o desenvolvimento de um módulo inteligente, que faz parte da arquitectura do projecto C-CAST, capaz de gerir toda a rede. Este mecanismo, dependendo do cenário da rede e do contexto dos utilizadores e das fontes, e em cooperação com outras entidades da rede, deve seleccionar a o caminho mais apropriado da rede de modo a fornecer da melhor forma o conteúdo aos utilizadores, e gerir a dinâmicidade da rede sempre que ocorrem mudanças. Para o implementar foi usada um método baseado na interacção de vários componentes, que trocam informação sobre contextos entre eles. O componente inteligente, usando informação actualizada da rede decide qual a melhor conexão da rede para servir cada utilizador. De forma a simular o comportamento da rede em várias situações, foram testados diversos cenários para avaliar a sua performance. A rede é avaliada de acordo com os vários parâmetros configurados, avaliando as melhorias conseguidas na performance da rede, por exemplo em termos de atrasos, rácio de pacotes perdidos e a carga imposta pelas mensagens de controlo da arquitectura. Através das simulações efectuadas é possível concluir que aplicando a arquitectura proposta, é fornecido de forma eficiente um serviço melhorado aos utilizadores, distribuindo o serviço de grupo com garantias de Qualidade de Serviço e usando informação de contexto

Avaliação de controlo de sessões multicast em redes com contexto

Mestrado em Engenharia Electrónica e TelecomunicaçõesOs utilizadores pretendem aceder, cada vez mais, a serviços multimédia com requisitos mais exigentes e personalizados. As limitações impostas pelos ambientes existentes (internet, 3G) para fornecer estes serviços levam à procura de melhores soluções, nomeadamente uma gestão eficaz das sessões multiparty. Neste tipo de soluções é normalmente utilizado o multicast, já que este permite reduzir os recursos utilizados, diminuindo o número de pacotes na rede. Contudo, o multicast não está consistente ao nível dos cenários de mobilidade, fundamentais nas redes de próxima geração. Actualmente existe uma vasta gama de tecnologias de acesso sem fios como WiFi, GPRS, UMTS e WiMAX. No futuro estas tecnologias diferentes complementar-se-ão convergindo numa infra-estrutura heterogénea capaz de fornecer um melhor serviço aos utilizadores, denominadas de redes 4G. A evolução dos terminais móveis também permitirá que estes se liguem simultaneamente a várias redes de acesso. Para uma melhor distribuição dos serviços dos utilizadores pelas redes de acesso disponíveis são necessários novos mecanismos de selecção. Uma nova selecção da rede baseada em informação de contexto (entidades e ambiente) tem tido grande relevo na comunidade científica. Assim, aplicações e rede reagem a alterações de contexto para uma melhor selecção da mesma. A dissertação apresentada encontra-se no âmbito do transporte multiparty com informação de contexto e reserva de recursos, permitindo a entrega do conteúdo de uma forma personalizada e com Qualidade de Serviço a vários utilizadores móveis, independentemente da tecnologia de acesso de cada um e da própria tecnologia da rede. Em suma, é utilizada uma arquitectura de rede baseada em informação de contexto e que reage eficazmente a alterações do mesmo. De forma a implementar a proposta apresentada recorreu-se à criação de várias entidades no simulador de redes NS-2. Os resultados foram obtidos usando diferentes cenários, avaliando a influência de cada parâmetro individualmente. Demonstrou-se que a arquitectura implementada permite suportar uma entrega dos conteúdos de uma maneira personalizada e independente da tecnologia utilizada. Obteve-se ainda uma boa gestão dos recursos da rede e uma melhoria na experiência percepcionada pelo utilizador através da selecção total da rede com base numa entidade de controlo central. A introdução do overlay de transporte multiparty melhora o comportamento geral da rede, minimizando as reconfigurações frequentes necessárias.Nowadays, more and more users want to access multimedia services with strong and personalized requirements. The limitations intrinsic to current environments (Internet and 3G) to provide this type of services motivate the research for an efficient management of multiparty sessions. The solution can also be based on multicast implementation, since it reduces resources utilization, decreasing the number of packets in the network. However, current multicast is not a strong solution in mobility scenarios, essential in next generation networks. Currently there is a wide range of wireless access technologies such as WiFi, GPRS, UMTS and WiMAX. In the future, these different technologies will converge in a complementary manner forming a heterogeneous infrastructure able to offer a better service to its users, usually named 4G. The evolution of mobile terminals will also allow them to connect simultaneously to several access networks. In order to a better distribution of the users services throughout available access networks, new selection mechanisms are required. A new network selection based on context information (entities and environments) is having a relevant role in scientific community. So, applications and networks react according to context changes, improving network selection. This Thesis is in the scope of context-aware multiparty transport with resources allocation, allowing the delivery of content in a personalized way with Quality of Service to several users, independently of the technology and the network. Resuming, the solution implements a context-aware network architecture that reacts efficiently to its changes. In order to implement this architecture, new entities were created in the network simulator NS-2. The results were obtained using different scenarios, evaluating the influence of each parameter independently. It was demonstrated that the integration of several components, allows a delivery of contents in a personalized manner and independently of the technology. The results showed a better management of the network resources and users experience, throughout the total network selection, based on a central control unit. The multiparty transport overlay improves the network behaviour, minimizing the necessary frequent reconfigurations

A decentralized framework for cross administrative domain data sharing

Federation of messaging and storage platforms located in remote datacenters is an essential functionality to share data among geographically distributed platforms. When systems are administered by the same owner data replication reduces data access latency bringing data closer to applications and enables fault tolerance to face disaster recovery of an entire location. When storage platforms are administered by different owners data replication across different administrative domains is essential for enterprise application data integration. Contents and services managed by different software platforms need to be integrated to provide richer contents and services. Clients may need to share subsets of data in order to enable collaborative analysis and service integration. Platforms usually include proprietary federation functionalities and specific APIs to let external software and platforms access their internal data. These different techniques may not be applicable to all environments and networks due to security and technological restrictions. Moreover the federation of dispersed nodes under a decentralized administration scheme is still a research issue. This thesis is a contribution along this research direction as it introduces and describes a framework, called \u201cWideGroups\u201d, directed towards the creation and the management of an automatic federation and integration of widely dispersed platform nodes. It is based on groups to exchange messages among distributed applications located in different remote datacenters. Groups are created and managed using client side programmatic configuration without touching servers. WideGroups enables the extension of the software platform services to nodes belonging to different administrative domains in a wide area network environment. It lets different nodes form ad-hoc overlay networks on-the-fly depending on message destinations located in distinct administrative domains. It supports multiple dynamic overlay networks based on message groups, dynamic discovery of nodes and automatic setup of overlay networks among nodes with no server-side configuration. I designed and implemented platform connectors to integrate the framework as the federation module of Message Oriented Middleware and Key Value Store platforms, which are among the most widespread paradigms supporting data sharing in distributed systems

Multihoming with ILNP in FreeBSD

Multihoming allows nodes to be multiply connected to the network. It forms the basis of features which can improve network responsiveness and robustness; e.g. load balancing and fail-over, which can be considered as a choice between network locations. However, IP today assumes that IP addresses specify both network location and node identity. Therefore, these features must be implemented at routers. This dissertation considers an alternative based on the multihoming approach of the Identifier Locator Network Protocol (ILNP). ILNP is one of many proposals for a split between network location and node identity. However, unlike other proposals, ILNP removes the use of IP addresses as they are used today. To date, ILNP has not been implemented within an operating system stack. I produce the first implementation of ILNP in FreeBSD, based on a superset of IPv6 – ILNPv6 – and demonstrate a key feature of ILNP: multihoming as a first class function of the operating system, rather than being implemented as a routing function as it is today. To evaluate the multihoming capability, I demonstrate one important application of multihoming – load distribution – at three levels of network hierarchy including individual hosts, a singleton Site Border Router (SBR), and a novel, dynamically instantiated, distributed SBR (dSBR). For each level, I present empirical results from a hardware testbed; metrics include latency, throughput, loss and reordering. I compare performance with unmodified IPv6 and NPTv6. Finally, I evaluate the feasibility of dSBR-ILNPv6 as an alternative to existing multihoming approaches, based on measurements of the dSBR’s responsiveness to changes in site connectivity. We find that multihoming can be implemented by individual hosts and/or SBRs, without requiring additional routing state as is the case today, and without any significant additional load or overhead compared to unicast IPv6