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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
141

P2Priv-TV - Mecanismo de privacidade em sistemas IPTV baseados em redes BitTorrent. / P2Priv-TV - Privacy mechanism in IPTV systems based on BitTorrent Networks.

Gomes, Marco Aurélio Lins 15 December 2015 (has links)
Serviços para entrega de conteúdo multimídia tem se tornado cada vez mais comuns com o advento de conexões mais rápidas à Internet. Porém, esse crescimento na base de usuários consumidores desse tipo de serviços, levam a gargalo de desempenho devido à restrições de recursos de infraestrutura. Para tentar reduzir tais restrições, análises na forma como o conteúdo pode ser entregue foram realizadas e novos mecanismos de entrega de conteúdo surgiram. Um desses mecanismos envolve o uso de redes P2P - Par a Par, no qual o usuário é consumidor e provedor de conteúdo para seus pares. Sistemas IPTV utilizando protocolos P2P estão se tornando populares pelo mundo, devido à descentralização da infraestrutura necessária para entrega do conteúdo, e redução do gargalo de desempenho. Um dos protocolos de rede P2P mais comum é BitTorrent, que é utilizado amplamente pelo mundo, devido à seu método descentralizado de compartilhar os dados. Dos trabalhos desenvolvidos utilizando este método, houve uma necessidade de avaliar os requisitos de segurança para garantir o funcionamento do sistema sem comprometer a infraestrutura ou o usuário. Porém, existem problemas de segurança em aberto, e o objetivo deste trabalho é o de analisar a privacidade do usuário enquanto utiliza o sistema. Para tanto, este trabalho propõe o P2Priv-TV, um mecanismo que garante que o conteúdo que um determinado usuário irá assistir não será de conhecimento dos demais usuários da rede. Este mecanismo é avaliado por meio de emulação para determinar sua viabilidade e eficácia. / There are many video streaming services available to users due to broadband connections popularity. These kind of service has increasing numbers of users and that may lead to performance bottlenecks because of shortage of infrastructure resources. To avoid shortages, there are many studies to think in a new way to deliver content and this lead to new deliver methods. One of these methods is the use of P2P (peer to peer) Networks, where the user is content consumer and provider to other peers. BitTorrent is the most popular P2P protocol widely used in the world and there are IPTV systems using this protocol as content delivery mechanism. P2P IPTV systems were developed and security issues were analyzed to ensure that users and system do not been compromised. However, there are other issues, and the goal of this work is to analyze user privacy in the system. This work presents the P2Priv-TV, a mechanism that ensure a user can consume a content without another user in the system knows about it. This mechanism will be analyzed using emulation to analyze feasibility and effectiveness.
142

Avaliação do uso de computação paralela utilizando uma rede P2P na simulação de dados climáticos: velocidade e direção do vento / Avaliação do uso de computação paralela utilizando uma rede P2P na simulação de dados climáticos: velocidade e direção do vento

Serckumecka, Adriano 17 July 2012 (has links)
Made available in DSpace on 2017-07-21T14:19:32Z (GMT). No. of bitstreams: 1 AdrianoSerckumecka.pdf: 825262 bytes, checksum: 9c527c3f506be1e58cf82ac8117dac67 (MD5) Previous issue date: 2012-07-17 / The main objective of this work is the evaluation of distributed systems based on peer-topeer network and parallel computing techniques to reduce response times of climate simulations. A probabilistic model for simulating wind data was used and two computing applications was implemented and evaluated. The first application was developed by using the framework P2PComp, which is directed to building parallel software and its deploy in P2P networks. The second application was developed without the support of this framework and using straightly the communication infrastructure software. Climatic data of the municipality of Lapa, Paraná comprising the period between 1998 and 2007 were used in the experiments. The results demonstrate the feasibility of using parallel computing and P2P networks for executing climate simulations. Best results, measured by the speedup obtained, were observed when using multiple peers (equal to 26) and when executing simulations for a long period of time ( near to 100 years). In such case, the speedup obtained is near to 7. / O objetivo principal deste trabalho é a avaliação de sistemas distribuídos baseados em redespar-a-par (P2P), juntamente com técnicas de computação paralela, para reduzir os tempos deresposta de simulações climáticas. Um modelo probabilístico específico para simulação de dados de vento foi adotado e duas aplicações computacionais foram implementadas e avaliadas.A primeira aplicação foi desenvolvida com o uso do Framework P2PComp, que permite a criação de programas paralelos e sua execução em redes P2P. A segunda aplicação adotou diretamente uma rede P2P, sem o uso desse framework, como infraestrutura de comunicação.Dados climáticos da região do Município de Lapa-PR, compreendendo o períıodo entre 1998 e 2007 foram empregados nos experimentos. Os resultados obtidos demonstram a viabilidade de utilização de computação paralela em redes P2P, nas simulações climáticas. Os melhores resultados medidos em relação ao fator de aceleração foram observados em situações onde foi utilizado um número maior de pares (igual a 26) e simulações climáticas para um período de tempo igual a 100 anos. Para este caso, o fator de aceleração obtido foi aproximadamente igual a 7.
143

Decentralized detection of violations f service level agreements using peer-to-peer technology

Nobre, Jéferson Campos January 2016 (has links)
Critical networked services established between service provider and customers are expected to operate respecting Service Level Agreements (SLAs). An interesting possibility to monitor such SLAs is using active measurement mechanisms. However, these mechanisms are expensive in terms of network devices resource consumption and also increase the network load because of the injected traffic. In addition, if the number of SLA violations in a given time is higher than the number of available measurement sessions (common place in large and complex network infrastructures), certainly some violations will be missed. The current best practice, the observation of just a subset of network destinations driven by human administrators expertise, is error prone, does not scale well, and is ineffective on dynamic network conditions. This practice can lead to SLA violations being missed, which invariably affect the performance of several applications. In the present thesis, we advocated the use of Peer-to-Peer (P2P) technology to improve the detection of SLA violations. Such use is described using principles to control active measurement mechanisms. These principles are accomplished through strategies to activate measurement sessions. In this context, the major contributions of this thesis are: i) An approach to improve the detection of SLA violations through the steering of the activation of active measurement sessions using local and remote past service level measurement results and resource utilization constraints; ii) The concept of destination rank as an approach to autonomically prioritize destinations for the activation of active measurement sessions using destination scores; iii) The concept of correlated peers to enable the autonomic provisioning of a P2P measurement overlay for the exchange of relevant active measurement results; iv) The concept of virtual measurement sessions to enable the sharing of measurement results among correlated peers in order to save network devices resources and to improve SLA monitoring coverage; v) The definition of decentralized strategies to steer the activation of active measurement sessions using P2P principles. The method used on the investigation started with the execution of literature reviews on the networkwide control of measurement mechanisms and the employment of P2P technology on network management. After that, the proposed principles to control active measurement mechanisms and the strategies to activate measurement sessions were described. Finally, experiments were performed to evaluate the performance as well as to highlight properties of such principles and strategies. The findings showed properties which improve the detection of SLA violations in terms of the number of detected violations and the adaptivity to network dynamics. We expect that such findings can lead to better SLA monitoring tools and methods.
144

Semear à preciso, viver nÃo à preciso: economia do compartilhamento e dispersÃo de sementes digitais atravÃs de redes P2P. / Seeding is necessary, living is not necessary: sharing economy and dispersion of digital seeds through P2P networks

Daniel Costa Valentim 12 May 2017 (has links)
CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior / A presente tese versa sobre compartilhamento de arquivos na era da internet. Analisaremos aspectos da socialidade em uma comunidade online especializada na arte do cultivo, semeio, preservaÃÃo e disseminaÃÃo de arquivos digitais (compreendidos enquanto âsementes digitaisâ). As sementes digitais sÃo basicamente qualquer arquivo de computador digitalizado (por exemplo, um filme, uma mÃsica, um livro, um software etc.) que necessita ser semeado virtualmente atà que floresÃa e possa ser compartilhado atravÃs da internet via redes P2P (peer-to-peer). Nesse sentido, esta tese à uma narrativa sobre uma experiÃncia relacional que vivenciamos (de 2008 a 2017) em uma comunidade de âcyberagricultoresâ denominada OÃsis (nome fictÃcio). O OÃsis à uma comunidade fechada que possui cerca de 60 mil membros registrados (atà inÃcio de 2017). Nossa perspectiva metodolÃgica nos levou a seguir linhas errÃticas dos traÃados digitais que compÃem as dinÃmicas singulares que constituem aquilo que denominamos de âeconomia do compartilhamentoâ. Deste modo, tentamos elucidar o movimento das sementes digitais atravÃs dos sensos de moralidades creditados pelos âsemeadores de arquivosâ que frequentam esta comunidade em particular. Com efeito, relatamos nesta tese prÃticas e vivÃncias que compÃem aquilo que identificamos como âÃtica do compartilharâ, espÃcie de âespÃrito do compartilhamentoâ que atua (atravÃs de uma alquimia simbÃlica) na transformaÃÃo de arquivos ou mercadorias digitais em presentes, dÃdivas e honrarias prontas para serem dispersadas atravÃs de redes cooperativas e descentralizadas de compartilhamento. Dito de outro modo, uma semente digital pode ser melhor apresentada sob a forma de uma âcoisa vivaâ, isto Ã, como uma semente de vida carregada de riquezas, dignidades e esperanÃas, exatamente por estabelecer o entendimento de que produÃÃes culturais sÃo artefatos produzidos para serem dispersados livremente como um âbem comumâ. Por fim, ressaltamos de que forma esta cyberecologia se apresenta como um projeto que pretende garantir a implantaÃÃo de uma rede de proteÃÃo de sementes digitais ameaÃadas pelo esquecimento e pelo descaso. / The present thesis deals with file sharing in the age of the Internet. We will analyze aspects of sociality in a file sharing community specialized in the art of cultivating, sowing, preserving of digital files (described as âdigital seedsâ). Digital seeds are basically any digitized computer file (for example, a movie, a song, a book, a software etc.) that needs to be virtually planted until it blooms and can be shared over the internet by P2P (peer-to-peer) networks. In this sense, this thesis is a narrative about a relational experience that we experienced (from 2008 to 2017) in a community of cyber seeders named Oasis (fictitious name). Oasis is a closed community that has about 60,000 registered members (until early 2017). Our methodological perspective led us to follow erratic digital paths that make up the unique dynamic that constitutes what we call "sharing economy". In this way, we try to elucidate the movement of digital seeds through the senses of morality credited by the "file sharers" who particularly attend that community. Indeed, in this thesis we report practices and experiences that make up what we identify as "ethics of sharing", a sort of "spirit of sharing" that acts (through a symbolic alchemy) in the transformation of digital files or goods into gifts and honors ready to be dispersed through cooperative and decentralized sharing networks. In other words, a digital seed can best be presented in the form of a "living thing"; that is, as a seed of life laden with riches, dignities and hopes, exactly for establishing the understanding that cultural productions are artifacts produced to be freely dispersed as a "common good." Finally, we highlight how this cyber ecology presents itself as a project that intends to ensure the implementation of a protection network of digital seeds threatened by forgetfulness and neglect.
145

"Semear à preciso, viver nÃo à preciso": economia do compartilhamento e dispersÃo de sementes digitais atravÃs de redes P2P / Seeding is necessary, living is not necessary: sharing economy and dispersion of digital seeds through P2P networks

Daniel Costa Valentim 12 May 2017 (has links)
CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior / A presente tese versa sobre compartilhamento de arquivos na era da internet. Analisaremos aspectos da socialidade em uma comunidade online especializada na arte do cultivo, semeio, preservaÃÃo e disseminaÃÃo de arquivos digitais (compreendidos enquanto âsementes digitaisâ). As sementes digitais sÃo basicamente qualquer arquivo de computador digitalizado (por exemplo, um filme, uma mÃsica, um livro, um software etc.) que necessita ser semeado virtualmente atà que floresÃa e possa ser compartilhado atravÃs da internet via redes P2P (peer-to-peer). Nesse sentido, esta tese à uma narrativa sobre uma experiÃncia relacional que vivenciamos (de 2008 a 2017) em uma comunidade de âcyberagricultoresâ denominada OÃsis (nome fictÃcio). O OÃsis à uma comunidade fechada que possui cerca de 60 mil membros registrados (atà inÃcio de 2017). Nossa perspectiva metodolÃgica nos levou a seguir linhas errÃticas dos traÃados digitais que compÃem as dinÃmicas singulares que constituem aquilo que denominamos de âeconomia do compartilhamentoâ. Deste modo, tentamos elucidar o movimento das sementes digitais atravÃs dos sensos de moralidades creditados pelos âsemeadores de arquivosâ que frequentam esta comunidade em particular. Com efeito, relatamos nesta tese prÃticas e vivÃncias que compÃem aquilo que identificamos como âÃtica do compartilharâ, espÃcie de âespÃrito do compartilhamentoâ que atua (atravÃs de uma alquimia simbÃlica) na transformaÃÃo de arquivos ou mercadorias digitais em presentes, dÃdivas e honrarias prontas para serem dispersadas atravÃs de redes cooperativas e descentralizadas de compartilhamento. Dito de outro modo, uma semente digital pode ser melhor apresentada sob a forma de uma âcoisa vivaâ, isto Ã, como uma semente de vida carregada de riquezas, dignidades e esperanÃas, exatamente por estabelecer o entendimento de que produÃÃes culturais sÃo artefatos produzidos para serem dispersados livremente como um âbem comumâ. Por fim, ressaltamos de que forma esta cyberecologia se apresenta como um projeto que pretende garantir a implantaÃÃo de uma rede de proteÃÃo de sementes digitais ameaÃadas pelo esquecimento e pelo descaso. / The present thesis deals with file sharing in the age of the Internet. We will analyze aspects of sociality in a file sharing community specialized in the art of cultivating, sowing, preserving of digital files (described as âdigital seedsâ). Digital seeds are basically any digitized computer file (for example, a movie, a song, a book, a software etc.) that needs to be virtually planted until it blooms and can be shared over the internet by P2P (peer-to-peer) networks. In this sense, this thesis is a narrative about a relational experience that we experienced (from 2008 to 2017) in a community of cyber seeders named Oasis (fictitious name). Oasis is a closed community that has about 60,000 registered members (until early 2017). Our methodological perspective led us to follow erratic digital paths that make up the unique dynamic that constitutes what we call "sharing economy". In this way, we try to elucidate the movement of digital seeds through the senses of morality credited by the "file sharers" who particularly attend that community. Indeed, in this thesis we report practices and experiences that make up what we identify as "ethics of sharing", a sort of "spirit of sharing" that acts (through a symbolic alchemy) in the transformation of digital files or goods into gifts and honors ready to be dispersed through cooperative and decentralized sharing networks. In other words, a digital seed can best be presented in the form of a "living thing"; that is, as a seed of life laden with riches, dignities and hopes, exactly for establishing the understanding that cultural productions are artifacts produced to be freely dispersed as a "common good." Finally, we highlight how this cyber ecology presents itself as a project that intends to ensure the implementation of a protection network of digital seeds threatened by forgetfulness and neglect.
146

P2Priv-TV - Mecanismo de privacidade em sistemas IPTV baseados em redes BitTorrent. / P2Priv-TV - Privacy mechanism in IPTV systems based on BitTorrent Networks.

Marco Aurélio Lins Gomes 15 December 2015 (has links)
Serviços para entrega de conteúdo multimídia tem se tornado cada vez mais comuns com o advento de conexões mais rápidas à Internet. Porém, esse crescimento na base de usuários consumidores desse tipo de serviços, levam a gargalo de desempenho devido à restrições de recursos de infraestrutura. Para tentar reduzir tais restrições, análises na forma como o conteúdo pode ser entregue foram realizadas e novos mecanismos de entrega de conteúdo surgiram. Um desses mecanismos envolve o uso de redes P2P - Par a Par, no qual o usuário é consumidor e provedor de conteúdo para seus pares. Sistemas IPTV utilizando protocolos P2P estão se tornando populares pelo mundo, devido à descentralização da infraestrutura necessária para entrega do conteúdo, e redução do gargalo de desempenho. Um dos protocolos de rede P2P mais comum é BitTorrent, que é utilizado amplamente pelo mundo, devido à seu método descentralizado de compartilhar os dados. Dos trabalhos desenvolvidos utilizando este método, houve uma necessidade de avaliar os requisitos de segurança para garantir o funcionamento do sistema sem comprometer a infraestrutura ou o usuário. Porém, existem problemas de segurança em aberto, e o objetivo deste trabalho é o de analisar a privacidade do usuário enquanto utiliza o sistema. Para tanto, este trabalho propõe o P2Priv-TV, um mecanismo que garante que o conteúdo que um determinado usuário irá assistir não será de conhecimento dos demais usuários da rede. Este mecanismo é avaliado por meio de emulação para determinar sua viabilidade e eficácia. / There are many video streaming services available to users due to broadband connections popularity. These kind of service has increasing numbers of users and that may lead to performance bottlenecks because of shortage of infrastructure resources. To avoid shortages, there are many studies to think in a new way to deliver content and this lead to new deliver methods. One of these methods is the use of P2P (peer to peer) Networks, where the user is content consumer and provider to other peers. BitTorrent is the most popular P2P protocol widely used in the world and there are IPTV systems using this protocol as content delivery mechanism. P2P IPTV systems were developed and security issues were analyzed to ensure that users and system do not been compromised. However, there are other issues, and the goal of this work is to analyze user privacy in the system. This work presents the P2Priv-TV, a mechanism that ensure a user can consume a content without another user in the system knows about it. This mechanism will be analyzed using emulation to analyze feasibility and effectiveness.
147

Airbnb is everything a hotel isn’t : En kvalitativ studie om resenärers motivation till logi tillhandahållen av Airbnb

Melissa, Pierre, Maija, Kongo January 2015 (has links)
Det blir idag allt vanligare att hyra logi via alternativa logidistributörer däribland Airbnb. Airbnb är ett webbcommunity som distribuerar boende för resenärer genom att på sin hemsida låta privatpersoner hyra ut sina egna bostäder. Syftet med denna studie är att kartlägga de faktorer som motiverar resenärer att välja logi genom Airbnb och vi ämnar i denna studie ta reda på detta genom att genomföra ett antal kvalitativa intervjuer. Intervjuerna fokuserar på respondenternas egna upplevelser som sedan analyseras. Intim turism, mänsklig motivation och P2P-resande är några av de teorier som uppsatsen berör. Genom analysen av det empiriska materialet har ett antal motivationsfaktorer identifierats som förklarar varför resenärer har valt att hyra logi via Airbnb framför andra logialternativ. Den primära motivationsfaktorn identifieras som den kulturella, då respondenterna upplever att de genom Airbnb får möjligheten att uppleva nya kulturer samt införskaffa sig ny kulturell kunskap. Sociala faktorer som exempelvis recensioner och betygssystem samt ekonomiska faktorer som pris spelar även in i valet av logidistributör. / It is today more common to rent accommodation through alternative accomodation distributors such as Airbnb. Airbnb is an online community that distributes accommodation for travelers through their website allowing individuals to rent their own housing. The purpose of this paper is to identify the factors that motivate travelers to choose accommodations through Airbnb, by conducting a number of qualitative interviews. The interviews focuses on the respondents' own stories which are being analyzed. Intimate tourism, human motivation and P2P traveling are some of the theories that are used in this paper. In the analysis of the empirical material, a number of motivational factors are identified that explain why travelers have chosen to rent accommodation through Airbnb over other lodging options. The primary motivation factor is identified as cultural, as the respondents feel that they through Airbnb get the opportunity to experience new cultures and acquiring new cultural knowledge. Social factors such as reviews and grading systems, as well as economic factors such as price also plays into the choice of accommodation distributor.
148

Decentralized detection of violations f service level agreements using peer-to-peer technology

Nobre, Jéferson Campos January 2016 (has links)
Critical networked services established between service provider and customers are expected to operate respecting Service Level Agreements (SLAs). An interesting possibility to monitor such SLAs is using active measurement mechanisms. However, these mechanisms are expensive in terms of network devices resource consumption and also increase the network load because of the injected traffic. In addition, if the number of SLA violations in a given time is higher than the number of available measurement sessions (common place in large and complex network infrastructures), certainly some violations will be missed. The current best practice, the observation of just a subset of network destinations driven by human administrators expertise, is error prone, does not scale well, and is ineffective on dynamic network conditions. This practice can lead to SLA violations being missed, which invariably affect the performance of several applications. In the present thesis, we advocated the use of Peer-to-Peer (P2P) technology to improve the detection of SLA violations. Such use is described using principles to control active measurement mechanisms. These principles are accomplished through strategies to activate measurement sessions. In this context, the major contributions of this thesis are: i) An approach to improve the detection of SLA violations through the steering of the activation of active measurement sessions using local and remote past service level measurement results and resource utilization constraints; ii) The concept of destination rank as an approach to autonomically prioritize destinations for the activation of active measurement sessions using destination scores; iii) The concept of correlated peers to enable the autonomic provisioning of a P2P measurement overlay for the exchange of relevant active measurement results; iv) The concept of virtual measurement sessions to enable the sharing of measurement results among correlated peers in order to save network devices resources and to improve SLA monitoring coverage; v) The definition of decentralized strategies to steer the activation of active measurement sessions using P2P principles. The method used on the investigation started with the execution of literature reviews on the networkwide control of measurement mechanisms and the employment of P2P technology on network management. After that, the proposed principles to control active measurement mechanisms and the strategies to activate measurement sessions were described. Finally, experiments were performed to evaluate the performance as well as to highlight properties of such principles and strategies. The findings showed properties which improve the detection of SLA violations in terms of the number of detected violations and the adaptivity to network dynamics. We expect that such findings can lead to better SLA monitoring tools and methods.
149

Um serviço de self-healing baseado em P2P para manutenção de redes de computadores / A P2P based self-healing service for coputer networks maintenance

Duarte, Pedro Arthur Pinheiro Rosa January 2015 (has links)
Observou-se nos últimos anos um grande aumetno na complexidade das redes. Surgiram também novos desa os para gerenciamento dessas redes. A dimensão atual e as tendências de crescimento das infraestruturas tem inviabilizado as técnicas de gerencimento de redes atuais, baseadas na intervenção humana. Por exemplo, a heterogeneidade dos elementos gerenciados obrigam que administradores e gerentes lidem com especi cidades de implanta ção que vão além dos objetivos gerenciais. Considerando as áreas funcionais da gerência de redes, a gerência de falhas apresenta impactos operacionais interessantes. Estima-se que 33% dos custos operacionais estão relacionados com a prevenção e recuperação de falhas e que aproximadamente 44% desse custo visa à resolução de problemas causados por erros humanos. Dentre as abordagens de gerência de falhas, o Self-Healing objetiva minimizar as interações humanas nas rotinas de gerenciamento de falhas, diminuindo dessa forma erros e demandas operacionais. Algumas propostas sugerem que o Self-Healing seja planejado no momento do projeto das aplicações. Tais propostas são inviáveis de aplicação em sistemas legados. Otras pesquisas sugerem à análise e instrumentação das aplicações em tempo de execução. Embora aplicáveis a sistemas legados, análise e instrumentação em tempo de execução estão fortemente acopladas as tecnologias e detalhes de implementação das aplicações. Por esse motivo, é difícil aplicar tais propostas, por exemplo, em um ambiente de rede que abrange muitas entidades gerenciadas implantadas através de diferentes tecnologias. Porém, parece plausível oferecer aos adminitradores e gerentes facilidades através das quais eles possam expressar seus conhecimentos sobre anoamlias e falhas de aplicações, bem como mecanismos através dos quais esses conhecimentos possam ser utilizado no gerenciamento de sistemas. Essa dissertação de mestrado tem como objetivo apresentar e avaliar uma solução comum que introduza nas redes capacidades de self-healing. A solu- ção apresentada utiliza-se de workplans para capturar o conhecimento dos administradores em como diagnosticar e recuperar anomalias e falhas em redes. Além disso, o projeto e implementação de um framework padrão para detecção e noti cação de falhas é discutido no âmbito de um sistema de gerenciamento baseado em P2P. Por último, uma avaliação experimental clari ca a viabilidade do ponto de vista operacional. / In recent years, a huge raise in networks' complexity was witnessed. Along the raise in complexity, many management challenges also arose. For instance, managed entities' heterogeneity demands administrators and managers to deal with cumbersome implementation and deployment speci cities. Moreover, infrastructures' current size and growth-trends show that it is becoming infeasible to rely on human-in-the-loop management techniques. Inside the problem domain of network management, Fault Management is appealing because of its impact in operational costs. Researches estimate that more than 33% of operational costs are related to preventing and recovering faults, where about 40% of this investment is directed to solve human-caused operational errors. Hence, addressing human interaction is mostly unarguably a need. Among di erent approaches, Self-Healing, a property of Autonomic Network Management's proposal, targets to avoid humans' interactions and decisions on Fault Management loops, thereupon unburden administrators and managers from performing Fault Management-related tasks. Some researches on Self-Healing enabling approaches suppose that Fault Management capabilities should be planned in design-time. These approaches are impossible to apply on legacy systems. Other researches suggest runtime analysis and instrumentation of applications' bytecode. Albeit applicable to some legacy systems, these last proposals are tightly-coupled to implementation's issues of underlaying technologies. For this reason, it is hard to apply such proposals end-toend, for example, in a scenario encompassing many managed entities implemented through di erent technologies. However, it is possible to o er to administrators and managers facilities to express they knowledge about networks' anomalies and faults, and facilities to leverage this knowledge. This master dissertation has as objective to present and evaluate a solution to imbue network management systems with self-healing capabilities. The solution relies on workplans as a mean to gather administrators and managers' knowledge on how to diagnose and heal networks' anomalies and faults. Besides that, the design and implementation of a standard framework for fault detection and noti cation customization is discussed while considering a P2P-Based Network Management System as its foundations. At last, an experimental evaluation renders clear the proposal's feasibility from the operational point of view.
150

Decentralized detection of violations f service level agreements using peer-to-peer technology

Nobre, Jéferson Campos January 2016 (has links)
Critical networked services established between service provider and customers are expected to operate respecting Service Level Agreements (SLAs). An interesting possibility to monitor such SLAs is using active measurement mechanisms. However, these mechanisms are expensive in terms of network devices resource consumption and also increase the network load because of the injected traffic. In addition, if the number of SLA violations in a given time is higher than the number of available measurement sessions (common place in large and complex network infrastructures), certainly some violations will be missed. The current best practice, the observation of just a subset of network destinations driven by human administrators expertise, is error prone, does not scale well, and is ineffective on dynamic network conditions. This practice can lead to SLA violations being missed, which invariably affect the performance of several applications. In the present thesis, we advocated the use of Peer-to-Peer (P2P) technology to improve the detection of SLA violations. Such use is described using principles to control active measurement mechanisms. These principles are accomplished through strategies to activate measurement sessions. In this context, the major contributions of this thesis are: i) An approach to improve the detection of SLA violations through the steering of the activation of active measurement sessions using local and remote past service level measurement results and resource utilization constraints; ii) The concept of destination rank as an approach to autonomically prioritize destinations for the activation of active measurement sessions using destination scores; iii) The concept of correlated peers to enable the autonomic provisioning of a P2P measurement overlay for the exchange of relevant active measurement results; iv) The concept of virtual measurement sessions to enable the sharing of measurement results among correlated peers in order to save network devices resources and to improve SLA monitoring coverage; v) The definition of decentralized strategies to steer the activation of active measurement sessions using P2P principles. The method used on the investigation started with the execution of literature reviews on the networkwide control of measurement mechanisms and the employment of P2P technology on network management. After that, the proposed principles to control active measurement mechanisms and the strategies to activate measurement sessions were described. Finally, experiments were performed to evaluate the performance as well as to highlight properties of such principles and strategies. The findings showed properties which improve the detection of SLA violations in terms of the number of detected violations and the adaptivity to network dynamics. We expect that such findings can lead to better SLA monitoring tools and methods.

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