Mittelständische und große Unternehmen sehen sich durch die rasant fortschreitende Digitalisierung von Medien und Kommunikation mit dem Problem konfrontiert, ihre Daten konsistent und logisch strukturiert zu verwalten. Häufig wird dieses Problem durch verteilte Strukturen (Filialen, Zweigstellen, Zulieferer, mobile Mitarbeiter) noch verstärkt. Die häufig verwendeten zentralisierten Strukturen (Server, Datenbanken) sind zudem ein wesentlicher Angriffspunkt für die Systemsicherheit und erfordern großen Aufwand zu ihrer Wartung und Aktualisierung.

Le but de cette thèse est de proposer des mécanismes efficaces pour l'ordonnancement des chunks et l'allocation de la bande passante dans le contexte de la transmission vidéo sur les réseaux P2P,afin d'offrir une meilleure qualité de service pour l'utilisateur final. Dans un premier temps nousavons proposé un mécanisme d'ordonnancement des chunks pour la transmission de vidéomulticouche dans les réseaux P2P. Le mécanisme proposé est basé sur une nouvelle technique quipermet de sélectionner les chunks adéquats et les demander des pairs les plus appropriés. Ensuitenous avons proposé un mécanisme d'allocation de la bande passante, toujours dans le cadre detransmission de vidéo multicouche dans les réseaux P2P. Le pair émetteur organise une enchère pour«vendre » sa bande passante. L'allocation tient en considération la priorité des pairs et l'importancedes couches demandées. Finalement nous avons proposé un mécanisme d'adaptation lisse « smooth» d'une vidéo multicouche transportée sur un réseau P2P.Après une introduction, nous présentons dans le chapitre 2 les motivations du travail le but du travailet les problèmes recherche qui demeurent. Dans ce chapitre nous présentons les composants dessystèmes P2P et tout particulièrement la distribution et l'adaptation de contenus. Dans ce cadre,nous proposons une classification des applications de streaming vidéo P2P ainsi que des mécanismesd'allocation de bande passante et d'ordonnancement pour le streaming pair-à-pair. Nous nousintéressons également aux techniques d'adaptation de la qualité en se focalisant plusparticulièrement sur la norme SVC (Scalable Video Coding).Le chapitre 3 propose des mécanismes de priorisation pour la planification de streaming P2P multicouches.Nous proposons une heuristique pour résoudre un problème général d'affectationgénéralisé (Generalized Assignment Problem – GAP). La solution présentée est ensuite adaptée aucas du streaming non multicouches. Les résultats issus des simulations montrent que les solutionsproposées donnent de meilleurs résultats que les solutions traditionnelles.Le chapitre 4 décrit un mécanisme d'allocation dynamique de la bande passante pour les réseaux destreaming P2P multicouches qui se base sur l'allocation d'une bande passante aux pairs tout enassurant un minimum de qualité de service à l'ensemble des pairs. Les bonnes performances desmécanismes proposés, qui sont détaillées à travers l'étude du ratio concernant l'utilisation de labande passante ainsi que du niveau de satisfaction des pairs, montrent que ces derniers permettentd'obtenir une utilisation optimale de la bande passante.Le chapitre 5 porte sur le lissage du streaming multicouches dans les réseaux P2P en se basant sur lesmétriques liées à la variation de la fréquence et de l'amplitude. Les mécanismes proposés ont étéimplémentés dans un banc d'essai réel et l'évaluation des performances montrent l'efficacité desmécanismes pour le lissage du streaming.Dans le chapitre 6 (conclusion and perspectives), nous résumons les contributions proposées danscette thèse ainsi qu’une ouverture sur les travaux futures / Recently we witnessed an increasing demand for scalable deployment of real-time multimediastreaming applications over Internet. In this context, Peer-to-Peer (P2P) networks are playing asignificant role for supporting large-scale and robust distribution of multimedia content to end-users.However, due to peers’ dynamicity, heterogeneity of terminals and access networks, the deploymentof real-time video streaming applications over P2P networks arises lot of challenges. Indeed, animportant issue in P2P overlays is the capacity to self-organize in the face of the dynamic behavior ofpeers in order to ensure content availability and continuity. In addition, the heterogeneity in networks,terminals, and P2P characteristics make the situation more challenging. In this context, layered videostreaming in P2P networks has drawn great interest to overcome these challenges, since it can notonly accommodate large numbers of users, but also handle heterogeneity of peers. However, there isstill a lack of comprehensive studies on video data blocks (chunks) scheduling and bandwidthallocation for the smooth playout in layered streaming over P2P networks.The aim of this thesis is to analyze these concerns and to propose an efficient real-time chunksscheduling and bandwidth allocation mechanisms for QoS provisioning of layered streamingapplications over P2P networks. Our contributions in this thesis are threefold. First, we propose ascheduling mechanism for layered P2P streaming. The proposed mechanism relies on a novelscheduling algorithm that enables each peer to select appropriate stream layers, along withappropriate peers to provide them. The presented mechanism makes efficient use of networkresources and provides high system throughput. Second, we propose a bandwidth allocation modelfor P2 layered streaming systems based on auction mechanisms to optimize the allocation of senderpeers’ uploads bandwidth. The upstream peers organize auctions to “sell” theirs items (links’bandwidth) according to bids submitted by the downstream peers taking into consideration the peerspriorities and the requested layers importance. The ultimate goal is to satisfy the quality levelrequirement for each peer, while reducing the overall streaming cost. Finally, we present a smoothingmechanism for layered streaming in P2P networks. The mechanism aims to reduce the number oflayer changes under varying network conditions, and ensure a smooth playout for the end-user.

A l’heure d’Internet, l’avenir du cinéma est en jeu. Les TIC nous font entrer dans une nouvelle ère dont la caractéristique centrale est le transport instantané de données immatérielles. Les modes de fonctionnement de la société, de l’économie et du droit d’auteur s’en trouvent bouleversés. L’adoption rapide des usages et l’extrême volatilité des modèles appellent à un ajustement des stratégies pour concilier développement technologique et juste rémunération des ayants droit. Avec la disparition de la notion de territorialité et la remise en cause du concept de propriété, l’Etat tente d’ajuster les diverses législations en vigueur et se lance dans une course de vitesse contre le numérique. L’industrie sort, quant à elle, progressivement d’une position défensive et s’efforce de développer des offres et services innovants. Mais la remise en cause de la chronologie des médias et l’arrivée d’une multitude d’acteurs qui ne participent pas au financement de la création, requièrent des solutions novatrices et de nature supranationale. S’il est important de faire évoluer les cadres juridiques et réglementaires pour soutenir et favoriser la distribution des films à la demande, il est également urgent de concevoir collectivement la manière dont les nouvelles pratiques de la génération connectée peuvent contribuer à un soutien équilibré de la production, condition fondamentale pour la pérennité du cinéma. Cette recherche pluridisciplinaire est une étude prospective qui vise à trouver des solutions concrètes en mesure de dépasser les stéréotypes et de réconcilier les motivations et contraintes des divers acteurs : industries, créateurs, publics, gouvernements. / With the growth of the Internet, the future of cinema is at stake. ICT ushers in a new era whose main characteristic is the instant transportation of immaterial data. The way society, the economy and copyrights work is undergoing dramatic shifts. New uses of technology are swiftly embraced and the volatility of models demands an adjustment of strategies so that technological development does not clash the right of owners’ fair payment. Territoriality is disappearing as a notion and property is being questioned as a concept. The State tries to adjust the different legislations in force and engages in a race against digital technologies. As for the industry itself, it is progressively forsaking its defensive stance and is striving to develop innovative offers and services. But the sequencing and the emergence of numerous new actors who do not participate in the financing of creation, call for modern and supranational solutions. While legal and regulatory frameworks need to evolve in order to sustain and encourage the distribution of on demand films, it is also urgent to collectively conceive a way for the digital natives’ new practices to contribute to a balanced support to production, which represents a fundamental condition to ensure the continued existence of cinema. This multidisciplinary research aims at finding actual solutions that will be able to overcome stereotypes as well as reconcile the motivations and constraints of the various actors: industries, creators, audiences, governments.

A arquitetura IP Multimedia Subsystem, proposta pelo consórcio 3rd Generation Partnership Project como base para o suporte à convergência entre telefonia móvel e a Internet, define uma série de elementos arquiteturais, entre os quais, o componente Call Session Control Function e o protocolo Session Initiation Protocol. Session Initiation Protocol é um protocolo da camada de aplicação utilizado para estabelecer, modificar e terminar sessões multimídia entre dispositivos. Em redes baseadas na arquitetura IP Multimedia Subsystem, o Session Initiation Protocol é o responsável pela comunicação entre dispositivos e a rede, e entre os componentes responsáveis pelo gerenciamento de sessão. Nos últimos anos, estudos detectaram degradação de desempenho em redes baseadas na arquitetura IP Multimedia Subsystem em função das características centralizadas do Session Initiation Protocol e dos componentes de gerenciamento de sessão. Este trabalho apresenta uma arquitetura distribuída para redes baseadas em IP Multimedia Subsystem, tendo como fundamento o paradigma de computação paralela baseado em espaço de tuplas onde os servidores são organizados em uma rede P2P, com objetivo de prover uma infraestrutura escalável e tolerante a falhas. A validação da arquitetura em termos de desempenho e escalabilidade se deu através de modelagem formal e simulação com Redes de Petri Coloridas. / The IP Multimedia Subsystem architecture, proposed by the 3rd Generation Partnership Project consortium as basis to support the convergence between mobile networks and the Internet, defines a set of architectural elements, among them, the Call Session Control Function and the Session Initiation Protocol. The Session Initiation Protocol is an application layer protocol used to establish, modify and terminate sessions between devices. On the IP multimedia subsystem based network, the Session Initiation Protocol play a key role on the communication between devices and the network, and between session management components. In the last years, studies have detected a performance bottleneck on IP multimedia subsystem networks due to centralized characteristic of the Session Initiation Protocol and in Session Control components. This work shows a distributed architecture for IP Multimedia Subsystem networks based on the tuple space paradigm, and the servers structured in a P2P network, aiming to achieve a scalable and fault-tolerant infrastructure. The validation of the architecture on the performance and scalability took place through the Coloured Petri Net formal modeling and simulation.

Diversos pesquisadores vêm investigando métodos e técnicas para tornar possível às pessoas anotarem vídeos de modo transparente. A anotação pode ser realizada com a fala, com o uso de tinta digital ou algum outro meio que possa ser capturado enquanto a pessoa assiste ao vídeo. Tais anotações podem ser compartilhadas com outras pessoas, que podem estar assistindo ao mesmo vídeo em um mesmo instante ou em momentos diferentes, sendo interessante ainda que as anotações possam ser realizadas por várias pessoas de modo colaborativo. O paradigma Watch-and-Comment (WaC) propõe a captura transparente de anotações multimodais de usuários enquanto os mesmos assistem e comentam um vídeo. Como resultado desse processo, é gerado um vídeo digital interativo integrando o conteúdo original às anotações realizadas. Esta dissertação tem por objetivo explorar conceitos de computação ubíqua, redes sociais, redes peer-to-peer e TV interativa na proposta de um modelo arquitetural de ciência de informações de contexto para aplicações definidas segundo o paradigma WaC. O modelo explora a integração de um serviço ao paradigma, que auxilie ou forneça alternativas para que aplicações, do momento da captura ao acesso das anotações, utilizem informações de contexto do usuário, do vídeo e das anotações. O modelo também auxilia no estudo de colaboração entre usuários que realizam anotações em vídeos. Outra contribuição da dissertação é a prototipação de aplicações para avaliar e refinar o modelo proposto. São apresentadas extensões para a aplicação WaCTool, considerando o uso de redes sociais e de alternativas para a anotação em vídeos / Researchers have been investigating methods and techniques to allow people to annotate videos ubiquitously. Annotations can be made using voice, digital ink or some other media that can be captured while a person watches a video. These annotations can be shared with other people, who can be watching a video on the same time or at a different one. Also, these annotations can be made by many people collaboratively. The Watch-and-Comment (WaC) paradigm aims at capturing multimodal annotations in an ubiquitous way, while users watch and comment some video. As a result, an interactive digital video is generated combining the original content and the annotations. The work reported on this thesis explores concepts such as ubiquitous computing, social networks, peer-to-peer networks and interactive digital TV, to propose an architectural context-aware model to the applications defined by WaC paradigm. The model proposes the integration of a new service to the paradigm, supporting applications on the annotation process by offering capture alternatives and using context information from user, video and annotations. Also, the model provides a study in collaborative annotation process. Another contribution of this thesis is the prototypes built to evaluate and upgrade the proposed model. The prototypes are extensions from WaCTool, considering the use of social networks and alternatives to annotate in videos

Apresenta-se o resultado de uma pesquisa destinada a propor um serviço para a resolução e descoberta de informações sobre objetos. Neste contexto, entendem-se como objetos os itens de uma cadeia produtiva e, como prováveis clientes do serviço proposto, sistemas de informação destinados ao gerenciamento de logística junto às cadeias produtivas e/ou à manutenção de dados sobre a rastreabilidade das cadeias. Encontram-se no mercado diversos sistemas de informação com estas características. A conveniência da troca de informações diretas entre os membros das cadeias produtivas, motiva diversos pesquisadores a propor a criação de padrões de dados. Uma das propostas mais relevantes, apresentada pela entidade internacional GS1, envolve a especificação de uma arquitetura para estes sistemas, bem como um vocabulário de dados padronizado, a Rede EPCglobal®. A utilização da tecnologia RFID permite a obtenção automática de dados, quando da passagem dos itens por leitores RFID instalados ao longo da cadeia produtiva. A utilização de um código padronizado, denominado Electronic Product CodeTM (EPC) na gravação das etiquetas RFID é outra vantagem desta tecnologia. Uma das funcionalidades essenciais deste sistema consiste na possibilidade de obtenção de informações relativas a um determinado produto. Estas informações podem se encontrar não somente no produtor do item, mas em todos os membros da cadeia produtiva que tiveram acesso ao item. Esta funcionalidade é o único aspecto da rede EPCglobal® ainda não especificada pelo GS1. Por esta razão, diversos pesquisadores têm-se dedicado à elaboração de propostas. O resultado desta pesquisa é mais uma delas. A solução apresentada baseia-se no uso de redes peer-to-peer (P2P), mais especificamente do protocolo Kademlia, escolhido a partir da comparação entre os vários protocolos propostos na literatura, visando a uma melhor eficácia. A partir de uma simulação efetuada em software especialmente desenvolvido para esta finalidade, apresentam-se os detalhes da sugestão e os resultados obtidos com sua utilização. / This is the result of a survey intended to propose a resolution and discovery service of information about objects. In this context, objects are items of a production chain and, likely customers of the proposed service, are information systems intended for logistics management at the productive chains and/or maintenance of data on traceability of supply chains. This scenario fits perfectly to the paradigm of the Internet of Things, where objects of everyday use have active participation on the Internet. The convenience of direct exchange of information between the members and the supply chains motivates many researchers to propose the creation of data standards. One of the most relevant proposals, presented by the international organization GS1, involves the architecture specification for these systems, as well as a standard data vocabulary, the EPCglobal® Network. The use of RFID technology allows obtaining data, during the passage of items by RFID readers installed along the supply chain. The use of a standardized code in the recording of RFID tags, called the Electronic Product CodeTM (EPC), is another advantage of this technology. One of the essential features of this system is the possibility of obtaining information relating to an individual product. This information can be found not only in item producer, but also in all members of the supply chain that had access to the item. This functionality is the only aspect of EPCglobal® not yet specified by GS1. For this reason, several researchers have been working with new suggestions. The solution presented is another proposal based on the use of an implementation of a peer-to-peer (P2P) network, using the Kademlia Protocol, chosen from the comparison between the several protocols proposed in the literature, aiming at a better effectiveness. From a simulation carried out in software specially developed for this purpose, we present the details of the suggestion and the results obtained with its use.

Les réseaux pair-à-pair (P2P) constituent un modèle de plus en plus populaire pour la programmation d’applications Internet car ils favorisent la décentralisation, le passage à l’échelle, la tolérance aux pannes et l’auto-organisation. à la différence du modèle traditionnel client-serveur, un réseau P2P est un système réparti décentralisé dans lequel tous les nœuds interagissent directement entre eux et jouent à la fois les rôles de fournisseur et d’utilisateur de services et de ressources. Une table de hachage distribuée (DHT) est réalisée par un réseauP2P et offre les mêmes services qu’une table de hachage classique, hormis le fait que les différents couples (clef, valeur) sont stockés dans différents nœuds du réseau. La fonction principale d’une DHT est la recherche d’une valeur associée à une clef donnée. Parmi les protocoles réalisant une DHT on peut nommer Chord, Pastry, Kademlia et Tapestry. Ces protocoles promettent de garantir certaines propriétés de correction et de performance ; or, les tentatives de démontrer formellement de telles propriétés se heurtent invariablement à des cas limites dans lesquels certaines propriétés sont violées. Tian-xiang Lu a ainsi décrit des problèmes de correction dans des versions publiées de Pastry. Il a conçu un modèle, appelé LuPastry, pour lequel il a fourni une preuve partielle, mécanisée dans l’assistant à la preuve TLA+ Proof System, démontrant que les messages de recherche de clef sont acheminés au bon nœud du réseau dans le cas sans départ de nœuds. En analysant la preuve de Lu j’ai découvert qu’elle contenait beaucoup d’hypothèses pour lesquelles aucune preuve n’avait été fournie, et j’ai pu trouver des contre-exemples à plusieurs de ces hypothèses. La présente thèse apporte trois contributions. Premièrement, je présente LuPastry+, une spécification TLA+ revue de LuPastry. Au-delà des corrections nécessaires d’erreurs, LuPastry+ améliore LuPastry en introduisant de nouveaux opérateurs et définitions, conduisant à une spécification plus modulaire et isolant la complexité de raisonnement à des parties circonscrites de la preuve, contribuant ainsi à automatiser davantage la preuve. Deuxièmement, je présente une preuve TLA+ complète de l’acheminement correct dans LuPastry+. Enfin, je démontre que l’étape finale du processus d’intégration de nœuds dans LuPastry (et LuPastry+) n’est pas nécessaire pour garantir la cohérence du protocole. Concrètement, j’exhibe une nouvelle spécification avec un processus simplifié d’intégration de nœuds, que j’appelle Simplified LuPastry+, et je démontre qu’elle garantit le bon acheminement de messages de recherche de clefs. La preuve de correction pour Simplified LuPastry+ est obtenue en réutilisant la preuve pour LuPastry+, et ceci représente un bon succès pour la réutilisation de preuves, en particulier considérant la taille de ces preuves. Chacune des deux preuves requiert plus de 30000 étapes interactives ; à ma connaissance, ces preuves constituent les preuves les plus longues écrites dans le langage TLA+ à ce jour, et les seuls exemples d’application de preuves mécanisées de théorèmes pour la vérification de protocoles DHT / A distributed hash table (DHT) is a peer-to-peer network that offers the function of a classic hash table, but where different key-value pairs are stored at different nodes on the network. Like a classic hash table, the main function provided by a DHT is key lookup, which retrieves the value stored at a given key. Examples of DHT protocols include Chord, Pastry, Kademlia and Tapestry. Such DHT protocols certain correctness and performance guarantees, but formal verification typically discovers border cases that violate those guarantees. In his PhD thesis, Tianxiang Lu reported correctness problems in published versions of Pastry and developed a model called {\LP}, for which he provided a partial proof of correct delivery of lookup messages assuming no node failure, mechanized in the {\TLA} Proof System. In analyzing Lu's proof, I discovered that it contained unproven assumptions, and found counterexamples to several of these assumptions. The contribution of this thesis is threefold. First, I present {\LPP}, a revised {\TLA} specification of {\LP}. Aside from needed bug fixes, {\LPP} contains new definitions that make the specification more modular and significantly improve proof automation. Second, I present a complete {\TLA} proof of correct delivery for {\LPP}. Third, I prove that the final step of the node join process of {\LP}/{\LPP} is not necessary to achieve consistency. In particular, I develop a new specification with a simpler node join process, which I denote by {\SLP}, and prove correct delivery of lookup messages for this new specification. The proof of correctness of {\SLP} is written by reusing the proof for {\LPP}, which represents a success story in proof reuse, especially for proofs of this size. Each of the two proofs amounts to over 32,000 proof steps; to my knowledge, they are currently the largest proofs written in the {\TLA} language, and---together with Lu's proof---the only examples of applying full theorem proving for the verification of DHT protocols

Submitted by Mariana Dornelles Vargas (marianadv) on 2015-05-19T19:12:55Z No. of bitstreams: 1 BSPonP2P.pdf: 2195234 bytes, checksum: 340cdfee0a4f8e27bd919cc3d5513c45 (MD5) / Made available in DSpace on 2015-05-19T19:12:55Z (GMT). No. of bitstreams: 1 BSPonP2P.pdf: 2195234 bytes, checksum: 340cdfee0a4f8e27bd919cc3d5513c45 (MD5) Previous issue date: 2014-08-29 / Nenhuma / Tecnologias constantemente estão avançando nas áreas de sistemas distribuídos e computação paralela. Isso acontece porque a compra de equipamentos eletrônicos esta acessível, por isso empresas, cada vez mais, estão apostando em soluções baratas para que todos tenham acesso. Consequentemente, existe um problema que é o desperdício na utilização destes equipamentos. Grande parte de seu tempo esses equipamentos ficam ociosos. Nesse contexto, esta dissertação apresenta o modelo BSPonP2P para minimizar o problema, buscando aproveitar esse desperdício para algum fim útil. O BSPonP2P utiliza uma abordagem de Computação em Grade P2P, ela visa utilizar os equipamentos para execução de computação útil. O objetivo e fazer as execuções de maneira concorrente. O BSPonP2P cria um ambiente com abordagens baseadas nos modelos estruturado e não estruturado vindos da arquitetura P2P, o que foi implementado para agilizar o gerenciamento da comunicação e das informações dentro da rede. Outro diferencial do modelo proposto e a utilização do modelo de programação paralela Bulk Synchronous Parallel (BSP), que cria um ambiente para execução de processos, validando as dependências e aprimorando a comunicação entre eles. A partir de avaliações de métricas como memória, computação, comunicação e dados de equipamentos, e criado um índice denominado de PM. Esse índice é avaliado periodicamente para definir migrações conforme a variável de ambiente a , que esta diretamente ligada as barreiras das supersteps. A partir de avaliações obtidas nas distribuições de processos em um ambiente heterogêneo criado, o modelo BSPonP2P se mostrou eficaz porque ele obteve bons resultados, como, por exemplo, na simples execução da aplicação, comparando com a execução do BSPonP2P, houve um aumento menor que 4% no tempo de execução. Além disso, na execução de 26 processos com 2000 Supersteps e a = 16, obteve-se um ganho de 6% a partir de 24 migrações de processos. Sendo assim, como contribuição científica, optou-se pela utilização de redes em Grades P2P com aplicações BSP, usando métricas como memória, computação, comunicação e dados de equipamentos para avaliação do ambiente. Além de, serviços como migração e checkpoint que possibilitaram um bom desempenho do modelo. / Technologies are constantly advancing in the areas of distributed systems and parallel computing. This is because the purchase of electronic equipment is accessible, so companies increasingly are betting on cheap solutions for every one to access. Accordingly, there is a problem that the wasteful use of such equipment. Most of these have access to the execution of computation, however, a large part of their time sit idle. In this context, this dissertation proposal presents BSPonP2P model to minimize the problem trying to enjoy this waste for any useful purpose. In the proposed model, a P2P Desktop Grid that seeks to use equipment to perform useful computing competitor among its users and Desktop Grid network users way approach will be used. The BSPonP2P will create an environment with models based on structured and unstructured P2P architecture approaches coming, that will be implemented to streamline the management and communication of information within the network. Another difference that the proposed model will have is the use of Bulk Synchronous Parallel (BSP) parallel programming model, which creates an environment for process execution dependencies validating and improving the communication between them. From reviews of metrics such as memory, computation, data communications equipment and an index called PM is created. This index is periodically valuated to define migration as the environment variable α, which is directly linked to the supersteps’ barriers. Based on the ratings obtained from the distributions of processes in a heterogeneous environment created, BSPonP2P model is demonstrated effective. This is because the model had good results, for example, the simple execution application compared to running the BSPonP2P there was a smaller increase than 4% in execution time. Moreover, the implementation of 26 cases with 2000 supersteps and alpha = 16 yielded a gain of 6% from 24 migration process. Thus, atom scientific contribution opted for the use of networks in P2P Grids with BSP applications using metrics such as memory, computation, communication and data equipment for environmental assessment.

Le routage par clé et par contenu sont des systèmes de routage ou la destination d'un message suit un parcours entre les nœuds du réseau qui dépend seulement du contenu du message même. On peut les trouver utilisés soit dans des systèmes pair-à-pair connus comme Réseaux Overlay Structurés (Structured Overlay Networks, SON), soit dans les architecture internet de nouvelle génération, les Réseaux Centrés sur les Contenus (Content-Centric Networks, CCN). Le but de cette thèse est double. D'un côté, on explore le sujet de l'interconnexion et de la coopération des réseaux d'overlay, et on propose une architecture capable de permettre à plusieurs réseaux d'overlay hétérogènes, avec différentes topologies et différents mécanismes de routage, d'interagir, grâce à une infrastructure basée sur des nœuds passerelles. On montre, par des moyennes de simulation et déploiement dans un réseaux réel, que la solution est scalable et permet un routage quasi-exhaustif avec un nombre relativement bas des nœuds passerelle bien connectés. De plus, on présente deux exemples d'applications qui pourront bénéficier de cette architecture. Dans une deuxième partie, on rentre plutôt dans les possibilités offertes par le routage basé sur les contenus hors sa "zone de confort": d'abord, on analyse les améliorations qu'un réseau d'overlay structuré peut porter à un système de diffusion vidéo pair-à-pair, en termes de qualité du vidéo et de perte des paquets pendant la transmission. Après, on examine un système entièrement centré sur le routage basé sur les contenus, en développant une solution de diffusion vidéo en temps réel dans un réseau CCN. / Key-based and content-based routing are a class of routing techniques where the destination and routing path for a message depends solely on the content of the message itself. This kind of routing has been implemented in certain peer-to-peer systems, known as Structured Overlay Networks (SON), or in the Next Generation Internet architectures, under the name of Content-Centric Networks (CCN). The scope of this thesis is twofold: on the one side, we explore the topic of the interconnection and cooperation of different structured overlays, and propose architecture capable of allowing several heterogeneous overlay networks, with different topologies and different routing schemes, to interact, thanks to a lightweight infrastructure consisting of co-located nodes. Through the use of simulations and real-world deployment, we show how this solution is scalable and how it facilitates quasi-exhaustive routing, with even a relatively low number of well-connected co-located nodes. To address the problem of scaling network design to millions of nodes, we propose a mathematical model capable of deriving basic performance figures for an interconnected system. Furthermore, we present two application examples that could greatly benefit from such architecture. On the other side, we investigate a little further into the capabilities of content-based routing outside of its "comfort zone": first, we analyze the improvement that a SON could bring to a peer-to-peer real-time video streaming system (P2P-TV), in terms of chunk loss and Quality of Experience. Then, we move the approach to a fully content-based domain, implementing the P2P-TV solution on top of Content-Centric Networks.

Apresenta-se o resultado de uma pesquisa destinada a propor um serviço para a resolução e descoberta de informações sobre objetos. Neste contexto, entendem-se como objetos os itens de uma cadeia produtiva e, como prováveis clientes do serviço proposto, sistemas de informação destinados ao gerenciamento de logística junto às cadeias produtivas e/ou à manutenção de dados sobre a rastreabilidade das cadeias. Encontram-se no mercado diversos sistemas de informação com estas características. A conveniência da troca de informações diretas entre os membros das cadeias produtivas, motiva diversos pesquisadores a propor a criação de padrões de dados. Uma das propostas mais relevantes, apresentada pela entidade internacional GS1, envolve a especificação de uma arquitetura para estes sistemas, bem como um vocabulário de dados padronizado, a Rede EPCglobal®. A utilização da tecnologia RFID permite a obtenção automática de dados, quando da passagem dos itens por leitores RFID instalados ao longo da cadeia produtiva. A utilização de um código padronizado, denominado Electronic Product CodeTM (EPC) na gravação das etiquetas RFID é outra vantagem desta tecnologia. Uma das funcionalidades essenciais deste sistema consiste na possibilidade de obtenção de informações relativas a um determinado produto. Estas informações podem se encontrar não somente no produtor do item, mas em todos os membros da cadeia produtiva que tiveram acesso ao item. Esta funcionalidade é o único aspecto da rede EPCglobal® ainda não especificada pelo GS1. Por esta razão, diversos pesquisadores têm-se dedicado à elaboração de propostas. O resultado desta pesquisa é mais uma delas. A solução apresentada baseia-se no uso de redes peer-to-peer (P2P), mais especificamente do protocolo Kademlia, escolhido a partir da comparação entre os vários protocolos propostos na literatura, visando a uma melhor eficácia. A partir de uma simulação efetuada em software especialmente desenvolvido para esta finalidade, apresentam-se os detalhes da sugestão e os resultados obtidos com sua utilização. / This is the result of a survey intended to propose a resolution and discovery service of information about objects. In this context, objects are items of a production chain and, likely customers of the proposed service, are information systems intended for logistics management at the productive chains and/or maintenance of data on traceability of supply chains. This scenario fits perfectly to the paradigm of the Internet of Things, where objects of everyday use have active participation on the Internet. The convenience of direct exchange of information between the members and the supply chains motivates many researchers to propose the creation of data standards. One of the most relevant proposals, presented by the international organization GS1, involves the architecture specification for these systems, as well as a standard data vocabulary, the EPCglobal® Network. The use of RFID technology allows obtaining data, during the passage of items by RFID readers installed along the supply chain. The use of a standardized code in the recording of RFID tags, called the Electronic Product CodeTM (EPC), is another advantage of this technology. One of the essential features of this system is the possibility of obtaining information relating to an individual product. This information can be found not only in item producer, but also in all members of the supply chain that had access to the item. This functionality is the only aspect of EPCglobal® not yet specified by GS1. For this reason, several researchers have been working with new suggestions. The solution presented is another proposal based on the use of an implementation of a peer-to-peer (P2P) network, using the Kademlia Protocol, chosen from the comparison between the several protocols proposed in the literature, aiming at a better effectiveness. From a simulation carried out in software specially developed for this purpose, we present the details of the suggestion and the results obtained with its use.