Existe um interesse crescente do mercado por aplicações de multimídia em streaming via rede. Particularmente, as aplicações de live streaming que utilizam a tecnologia de redes P2P para a disseminação de conteúdo têm sido alvo de grande atenção. Aplicações como PPLive e PPStream provam que as aplicações de live streaming em redes P2P são uma realidade com relação à tecnologia atual. Os sistemas de live streaming fornecem um serviço de multicast no nível de aplicação para transmissões ao vivo na Internet. Essas aplicações de live streaming, quando executadas em redes P2P, têm potencial para serem altamente robustas, escaláveis e adaptativas devido à redundância e não dependência de recursos particulares dentre os nodos participantes. Porém, para fazer uso de todas as vantagens disponíveis, a aplicação deve contornar alguns desafios: i) manter a qualidade de playback mesmo com a inerente dinamicidade das redes P2P; ii) impedir que nodos incorretos escondam ações maliciosas atrás do anonimato que existe em P2P; iii) manter a taxa de upload dos nodos participantes da aplicação em um nível aceitável. A taxa de upload dos nodos é muito importante porque a aplicação de live streaming em P2P é uma aplicação cooperativa. Desta forma, esperase que todo novo usuário ajude a aplicação retransmitindo pacotes para outros usuários, mantendo, desta forma, a capacidade global de upload do sistema. Infelizmente, manter a cooperação em live streaming não é uma tarefa trivial, visto que cada nodo enfrenta o dilema social do interesse próprio (individualmente é melhor explorar a cooperação dos outros usuários sem reciprocidade) versus a cooperação para com o grupo. A principal contribuição deste trabalho consiste na apresentação de um modelo matemático baseado em Teoria dos Jogos Evolucionários, cujo objetivo é ajudar a compreender as aplicações de live streaming em redes P2P e os fatores que influenciam o seu correto funcionamento. Como contribuição secundária, este trabalho fornece uma análise estatística do comportamento do download e upload observado nestas aplicações. A análise estatística mostra que existe um decaimento da variância temporal de download e upload nas aplicações de live streaming, e que tal decaimento segue uma lei de potência. Os resultados evolucionários do modelo indicam que, se a queda do índice de satisfação dos usuários com a taxa de download for suave, e se a redução da satisfação devido ao custo de upload for insignificante, então existe um ambiente propício para que a cooperação entre os nodos cresça. De forma inversa, se a queda do índice de satisfação dos usuários com a taxa de download for abrupta, e a redução da satisfação devido ao custo de upload for significativa, então existe um ambiente propício para proliferação de nodos oportunistas. A realização e descrição desta pesquisa é composta de quatro etapas principais: i) a delimitação do cenário de live streaming e a definição do jogo para modelagem; ii) a definição do conjunto de estratégias e da função de utilidade; iii) a criação do modelo; iv) a análise do modelo e a apresentação dos resultados de simulação. A análise do modelo abrange três fases: i) análise estatística e comparação das características de download e upload dos dois simuladores utilizados; ii) avaliação do modelo de Teoria dos Jogos Evolucionários através de simulações; e iii) análise dos resultados evolucionários gerados pelo simulador de Teoria dos Jogos Evolucionários. / There is a growing interest in the market for networked multimedia applications. Live streaming applications that use the technology of P2P networks for distribution of live content have specially been the subject of great attention. Applications such as PPLive and PPStrem demonstrate that P2P live streaming applications are already possible with our present technology. Live streaming systems provide a multicast service in the application level for live broadcasts to users through the Internet. These systems executing in P2P networks have the potential to be highly robust, scalable and adaptive due to the characteristics of these scenarios. However, to take advantage of these potential properties, they must overcome some challenges: i) to maintain the playback quality even with the inherent dynamics of P2P networks; ii) to prevent that incorrect peers hide malicious behavior behind their anonymity; iii) to maintain the upload contribution of peers at acceptable levels. The upload contribution of peers is highly important because live streaming applications are cooperative applications. Therefore, every new user must help the application forwarding packets to other users, thereby maintaining the global upload capacity of the system. Unfortunately, the maintenance of cooperation in live streaming system is not a trivial task, since each node faces the social dilemma of self-interest (individually is always better to explore the cooperation of other users without reciprocity) versus cooperation to the group. The main contribution of this dissertation is the presentation of a mathematical model based on Evolutionary Game Theory, whose goal is to help understanding live streaming P2P applications and the factors that influence their correct operation. As a secondary contribution, this work provides a statistical analysis of download and upload behaviors of peers in live streaming P2P systems. The statistical analysis indicates that there is a decay in the download and upload variances, and that this decay follows a power law. The evolutionary results of the model indicate that, if the satisfaction of users with the download rate is smooth, and the reduction of satisfaction due to the upload cost is negligible, then there is a favorable environment for the growth of cooperation. Conversely, if the satisfaction of users with the download rate is abrupt, and the reduction of satisfaction due to the upload cost is significant, then there is a favorable environment to the proliferation of opportunistic nodes. The realization and description of this research is composed of four main steps: i) the definition of the live streaming scenario and the definition of the game to model this scenario; ii) the definition of the strategy set and of the utility function; iii) the suggestion of a model; iv) the analysis of the proposed model and the presentation of obtained results. The model analysis comprehends three phases: i) the statistical analysis and the comparison of the characteristics of download and upload of the two simulators used in this work; ii) the evaluation of the Evolutionary Game Theory model through simulation; and iii) the analysis of the results generated by the Evolutionary Game Theory simulator.

Existe um interesse crescente do mercado por aplicações de multimídia em streaming via rede. Particularmente, as aplicações de live streaming que utilizam a tecnologia de redes P2P para a disseminação de conteúdo têm sido alvo de grande atenção. Aplicações como PPLive e PPStream provam que as aplicações de live streaming em redes P2P são uma realidade com relação à tecnologia atual. Os sistemas de live streaming fornecem um serviço de multicast no nível de aplicação para transmissões ao vivo na Internet. Essas aplicações de live streaming, quando executadas em redes P2P, têm potencial para serem altamente robustas, escaláveis e adaptativas devido à redundância e não dependência de recursos particulares dentre os nodos participantes. Porém, para fazer uso de todas as vantagens disponíveis, a aplicação deve contornar alguns desafios: i) manter a qualidade de playback mesmo com a inerente dinamicidade das redes P2P; ii) impedir que nodos incorretos escondam ações maliciosas atrás do anonimato que existe em P2P; iii) manter a taxa de upload dos nodos participantes da aplicação em um nível aceitável. A taxa de upload dos nodos é muito importante porque a aplicação de live streaming em P2P é uma aplicação cooperativa. Desta forma, esperase que todo novo usuário ajude a aplicação retransmitindo pacotes para outros usuários, mantendo, desta forma, a capacidade global de upload do sistema. Infelizmente, manter a cooperação em live streaming não é uma tarefa trivial, visto que cada nodo enfrenta o dilema social do interesse próprio (individualmente é melhor explorar a cooperação dos outros usuários sem reciprocidade) versus a cooperação para com o grupo. A principal contribuição deste trabalho consiste na apresentação de um modelo matemático baseado em Teoria dos Jogos Evolucionários, cujo objetivo é ajudar a compreender as aplicações de live streaming em redes P2P e os fatores que influenciam o seu correto funcionamento. Como contribuição secundária, este trabalho fornece uma análise estatística do comportamento do download e upload observado nestas aplicações. A análise estatística mostra que existe um decaimento da variância temporal de download e upload nas aplicações de live streaming, e que tal decaimento segue uma lei de potência. Os resultados evolucionários do modelo indicam que, se a queda do índice de satisfação dos usuários com a taxa de download for suave, e se a redução da satisfação devido ao custo de upload for insignificante, então existe um ambiente propício para que a cooperação entre os nodos cresça. De forma inversa, se a queda do índice de satisfação dos usuários com a taxa de download for abrupta, e a redução da satisfação devido ao custo de upload for significativa, então existe um ambiente propício para proliferação de nodos oportunistas. A realização e descrição desta pesquisa é composta de quatro etapas principais: i) a delimitação do cenário de live streaming e a definição do jogo para modelagem; ii) a definição do conjunto de estratégias e da função de utilidade; iii) a criação do modelo; iv) a análise do modelo e a apresentação dos resultados de simulação. A análise do modelo abrange três fases: i) análise estatística e comparação das características de download e upload dos dois simuladores utilizados; ii) avaliação do modelo de Teoria dos Jogos Evolucionários através de simulações; e iii) análise dos resultados evolucionários gerados pelo simulador de Teoria dos Jogos Evolucionários. / There is a growing interest in the market for networked multimedia applications. Live streaming applications that use the technology of P2P networks for distribution of live content have specially been the subject of great attention. Applications such as PPLive and PPStrem demonstrate that P2P live streaming applications are already possible with our present technology. Live streaming systems provide a multicast service in the application level for live broadcasts to users through the Internet. These systems executing in P2P networks have the potential to be highly robust, scalable and adaptive due to the characteristics of these scenarios. However, to take advantage of these potential properties, they must overcome some challenges: i) to maintain the playback quality even with the inherent dynamics of P2P networks; ii) to prevent that incorrect peers hide malicious behavior behind their anonymity; iii) to maintain the upload contribution of peers at acceptable levels. The upload contribution of peers is highly important because live streaming applications are cooperative applications. Therefore, every new user must help the application forwarding packets to other users, thereby maintaining the global upload capacity of the system. Unfortunately, the maintenance of cooperation in live streaming system is not a trivial task, since each node faces the social dilemma of self-interest (individually is always better to explore the cooperation of other users without reciprocity) versus cooperation to the group. The main contribution of this dissertation is the presentation of a mathematical model based on Evolutionary Game Theory, whose goal is to help understanding live streaming P2P applications and the factors that influence their correct operation. As a secondary contribution, this work provides a statistical analysis of download and upload behaviors of peers in live streaming P2P systems. The statistical analysis indicates that there is a decay in the download and upload variances, and that this decay follows a power law. The evolutionary results of the model indicate that, if the satisfaction of users with the download rate is smooth, and the reduction of satisfaction due to the upload cost is negligible, then there is a favorable environment for the growth of cooperation. Conversely, if the satisfaction of users with the download rate is abrupt, and the reduction of satisfaction due to the upload cost is significant, then there is a favorable environment to the proliferation of opportunistic nodes. The realization and description of this research is composed of four main steps: i) the definition of the live streaming scenario and the definition of the game to model this scenario; ii) the definition of the strategy set and of the utility function; iii) the suggestion of a model; iv) the analysis of the proposed model and the presentation of obtained results. The model analysis comprehends three phases: i) the statistical analysis and the comparison of the characteristics of download and upload of the two simulators used in this work; ii) the evaluation of the Evolutionary Game Theory model through simulation; and iii) the analysis of the results generated by the Evolutionary Game Theory simulator.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-05-30T20:25:10Z No. of bitstreams: 1 franciscohenriquecerdeiraferreira.pdf: 1810078 bytes, checksum: b5d9796bdd636be5e4f0f3212220ad0a (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-06-01T11:36:20Z (GMT) No. of bitstreams: 1 franciscohenriquecerdeiraferreira.pdf: 1810078 bytes, checksum: b5d9796bdd636be5e4f0f3212220ad0a (MD5) / Made available in DSpace on 2017-06-01T11:36:20Z (GMT). No. of bitstreams: 1 franciscohenriquecerdeiraferreira.pdf: 1810078 bytes, checksum: b5d9796bdd636be5e4f0f3212220ad0a (MD5) Previous issue date: 2013-03-11 / Nos últimos anos, as aplicações P2P de transmissão de vídeo ao vivo despertaram um grande interesse na comunidade cientí ca. Essas aplicações geram um grande volume de dados que afetam diretamente o desempenho da rede. Apesar de existir um grande número de trabalhos dedicados a entender as aplicações P2P de transmissão de vídeo ao vivo, a maioria deles se baseia em uma visão estática desses sistemas. Estes trabalhos não se preocupam em entender a dinâmica do sistema, ou seja, como eles evoluem ao longo do tempo. Através de experimentos realizados na plataforma PlanetLab, este trabalho apresenta uma caracterização da aplicação SopCast, um dos mais importantes sistemas P2P de transmissão de vídeo ao vivo. O estudo é realizado levando-se em consideração a dinamicidade da topologia construída. Também é investigada a formação de comunidades na rede sobreposta e a correlação dessas comunidades com os Sistemas Autônomos da Internet (AS). Os resultados mostram que a formação de comunidades é bem de nida pela troca de tráfego e uma pequena porção de participantes desses grupos é responsável por sustentar toda a comunidade. Além disso, não existe indícios que os participantes se agrupam de acordo com seus Sistemas Autônomos. De fato, a probabilidade de uma comunidade ser formada com mais da metade de membros pertencentes a um mesmo AS é inferior a 10%. Finalmente, as caracterizações apresentadas fornecem informações importantes para o desenvolvimento de novas aplicações P2P de transmissão de vídeo ao vivo. Mais que isso, será possível algoritimos de formação de parcerias e grupos de tal forma que seja possível reduzir os custos de transmissão entre redes diferentes. / P2P live streaming systems have attracted a lot of attention from the research community in the last years. Such systems generate a large amount of data which impacts the network performance. Despite large number of works devoted to understand P2P live streaming applications, most of them rely on characterizing the static view of these systems. These works do not worry about either understanding the systems dynamics or analyzing how it evolves over time. Through experiments in PlanetLab platform, we present a characterization of the SopCast application, one of the most important P2P live streaming system. We focus on characterizing the dynamics of P2P overlay topology. We also investigated the community formation process in SopCast overlay and the correlation of these communities with the Autonomous Systems of the Internet (AS). Our results show that the formation of communities is well de ned by the exchange of tra c and a small portion of peers of these groups is responsible for supporting the entire community. Furthermore, there is a evidence that peeers are not grouped according to their Autonomous Systems. Indeed, the probability of a community be formed with more 50% of members belonging to the same AS is less than 10%. Finally, the characterizations we conduct provide important information to new P2P live streaming protocols and membership algorithms design. Moreover, the presented characterization may be useful to developers create algorithms that reduces the transmission cost on the P2P network.

El objetivo de este estudio realizado es para que el público tenga más en cuenta lo que un movimiento urbano o una cultura urbana puede llegar a crecer y evolucionar con el paso de tiempo. El freestyle es un movimiento que empezó por los ochenta en Brooklyn, Estados Unidos, desde ese entonces ha sido catalogado por varios calificativos negativos por el mismo hecho que iniciado en la calle, por ejemplo, la violencia, la delincuencia, etc. Con el paso del tiempo, el freestyle ha evolucionado de manera increíble. antes del 2010, solo había un evento por año, hoy en día hay más de dos eventos por mes. Esto se ha debido por varios factores, tanto como los mismos freestylers, la comunidad de freestyle, el live streaming, etc. Por ello, la pregunta de investigación es: ¿Cómo el live stream ha beneficiado el crecimiento de The Urban Roosters en los últimos 3 años? En este contexto, la investigación ha ayudado explorar esos beneficios que se ha ido otorgando con el pasar de los años y los motivos también. La pregunta de investigación se responde a través de los estudios que se ha realizado en transcurso de todo este periodo. se ha indagado por fuentes confiables que han aportado con datos importantes, de esa manera se pueda entender todo el tema a más profundidad. Si bien es cierto, ha habido varios factores importantes para el tema, se han tomado en cuento los que han sido más relevantes e importantes en transcurso de los años. / The main reason of this investigation is to make the public more aware of what an urban movement or urban culture can grow and evolve over the pass of time. Freestyle is a movement that began in the eighties in Brooklyn, United States, since then it has been classified by several negative labels for the same fact that it started on the street, for example, violence, crime, etc. Over time, freestyle has grown and evolved in an incredible way. Before 2010, there was only one event per year, nowadays there are more than two events per month. This has been due to several factors, as well as the freestylers themselves, the freestyle community, live streaming, etc. So, the research question is: How has live streaming benefited The Urban Roosters' growth in the past 3 years? In this context, the research that I´ve been looking for has helped explore those benefits that have been granted over the years and the reasons as well. The research question is answered through the studies that have been carried out throughout this period. It has been investigated by reliable sources that have provided important data, so that the whole topic can be understood in more depth. Although it is true, there have been several important factors for the subject, those that have been most relevant and important over the years have been taken into account. / Trabajo de investigación

In this thesis, we explore the use of a centrally-coordinated peer-to-peer overlay as a possible solution to the live streaming problem. Our contribution lies in showing that such approach is indeed feasible given that a number of key challenges are met. The motivation behind exploring an alternative design is that, although a number of approaches have been investigated in the past, e.g. mesh-pull and tree-push, hybrids and best-of-both-worlds mesh-push, no consensus has been reached on the best solution for the problem of peer-to-peer live streaming, despite current deployments and reported successes. In the proposed system, we model sender/receiver peer assignments as an optimization problem. Optimized peer selection based on multiple utility factors, such as bandwidth availability, delays and connectivity compatibility, make it possible to achieve large source bandwidth savings and provide high quality of user experience. Clear benefits of our approach are observed when Network Address Translation constraints are present on the network. We have addressed key scalability issues of our platform by parallelizing the heuristic which is the core of our optimization engine and by implementing the resulting algorithm on commodity Graphic Processing Units (GPUs). The outcome is a Linear Sum Assignment Problem (LSAP) solver for time-constrained systems which produces near-optimal results and can be used for any instance of LSAP, i.e. not only in our system.   As part of this work, we also present our experience in working with Network Address Translators (NATs) traversal in peer-to-peer systems. Our contribution in this context is threefold. First, we provide a semi-formal model of state of the art NAT behaviors. Second, we use our model to show which NAT combinations can be theoretically traversed and which not. Last, for each of the combinations, we state which traversal technique should be used. Our findings are confirmed by experimental results on a real network. Finally, we address the problem of reproducibility in testing, debugging and evaluation of our peer-to-peer application. We achieve this by providing a software framework which can be transparently integrated with any already-existing software and which is able to handle concurrency, system time and network events in a reproducible manner. / QC 20110426

In the previous two decades, live streaming has become a popular trend in the music industry. From TV and radio broadcast to live streaming on social media, the relationship between audience and performers has been transforming over time. In 2019, due to the sudden spread of Covid-19, the popularity of watching live streaming events reached an unprecedently peak. According to some market studies, this trend will continue even when the pandemic will be over. This research aims to explore how live streaming has changed the interaction between audiences and performers as a consequence of this great event.  In order to understand the current music live-streaming culture, an online survey, interviews and field studies were conducted to obtain insights about potential problems and needs in live streaming. Through the project, a new design feature, the “Cheering” function, is suggested as an additional function to the existing live-streaming platforms, to enhance and enrich the interaction between audience and performers.

A mainstream course has several components that deaf and hard-of-hearing (DHH) students must reconcile. In class, components can include the instructor, projection display, whiteboard, interpreting, and real-time captioning. Outside the classroom, components can include materials from the instructor, notes generated by a note-taker, and a lecture transcript generated via real-time captioning. Web conferencing software can be harnessed to create inclusive experiences for DHH students. Such software can place all components of a class session on a single screen to create a composite screen solution that can be viewed by students in real-time and recorded for later, self-paced review. A composite screen solution may increase performance and comprehension of DHH students in mainstream courses, along with their hearing counterparts. This mixed-methods study focused on the implementation of web conferencing software in a mainstream, college course to explore utilization of a composite screen solution by students inside the classroom. Quantitative data were collected and analyzed to determine impact on student performance. Qualitative data were also collected and analyzed to investigate participant perceptions about the intervention. There was no significant impact on student performance found based on student self-selected usage of the composite screen solution throughout the term. Hearing students utilized the composite screen solution significantly more than DHH students to compensate for obstructed views due to the design of a classroom and to make follow-along demonstrations easier. Alternatively, DHH students had unobstructed views with the projection screen and ASL interpreter in their field of vision. Overall, the live stream of the composite screen solution was not widely utilized by the intended target audience, DHH students, as anticipated. Instead, the results illustrate the importance of design and how a solution has the potential to help an unintended audience with unanticipated issues. The generalizability of the results, as they pertain to DHH students, are limited given the number of DHH participants.

Storskaliga öppna nätbaserade kurser, MOOCar, med självstyrd studietakt skapar en lärandesituation där kursdeltagaren står i centrum och aktivt kan påverka sin egen studieprocess. Ett problem som kursdeltagare upplever är att de får begränsat stöd och hjälp av lärare eller andra kursdeltagare. Möjligheten till social interaktion är avgörande för främjandet av lärandeprocessen i nätbaserade utbildningar visar tidigare forskning. Studien ämnar därför att utforska om direktuppspelning (livestreaming) kan användas som ett pedagogiskt verktyg för att främja den sociala interaktionen mellan kursdeltagare samt mellan kursdeltagare och lärare i MOOCar med självstyrd studietakt. Utifrån en systematisk litteraturstudie utformades ett moment med direktuppspelning via Twitch som testades i praktiken i en MOOC som gavs av Kungliga Tekniska högskolan (KTH). Vi utvärderade sedan momentet genom en enkät till kursdeltagarna och intervju med läraren. En intervju genomfördes också med ytterligare en lärare på KTH som tidigare genomfört ett antal kursmoment där direktuppspelning använts. MOOCar karakteriseras av att de skall vara tillgängliga för alla, därav valdes användarvänlig och kostnadsfri plattform och programvara. På grund av att en direktuppspelning inom MOOCar ska kunna stödja ett stort deltagarantal gavs kursdeltagarna enbart möjlighet att kommunicera via chatt medan läraren kunde kommunicera via såväl chatt som ljud och video. Studien visade att såväl kursdeltagare som lärarna upplevde direktuppspelning som ett givande komplement till de kommunikationsmöjligheter som redan ges i MOOCar med självstyrd studietakt men att läraren bär ett stort ansvar i att möjliggöra de sociala interaktionerna som direktuppspelning ger möjlighet till. Direktuppspelning visades även ge en personlig kontakt som kan hjälpa minimera känslan av att vara isolerad. Baserat på studien utformades en manual för att underlätta implementeringen för lärare i framtida kurser. / Self-paced massive open online courses, MOOCs, provide individual learners with the opportunity to take control of their learning. However, MOOCs require learners to be able to fulfil the course with limited help from teachers and peers - something that is highlighted as an essential factor to enhance the learning experience in distance education. Therefore this study aims to explore the use of live streaming as a pedagogic tool in self-paced MOOCs to enhance communication between learners and between learners and the teacher. Based on a systematic literature study, a live streaming event was designed and conducted via Twitch in a self-paced MOOC given by KTH Royal Institute of Technology. To evaluate the event surveys were handed out to the learners and the teacher was interviewd. An interview was also conducted with another teacher at KTH who had experience with planning and executing live streaming events. Since MOOCs are characterized as being accessible to everyone a user-friendly and free platform plus software were selected. Due to the fact that a live streaming event in MOOCs must be able to support a large number of learners, we chose to allow learners to communicate only via chat while the teacher was able to communicate via chat, audio and video. The study showed that both the learners and the teacher perceived this moment as a rewarding complement to the opportunities for communication already provided in self-paced MOOCs but that the teacher has a major responsibility in enabling the interactions that live streaming allows. The teacher also felt that live streaming provided a personal contact and could therefore be a means to minimize the sense of isolation that is often associated with self-paced MOOCs. The study further designed a manual to facilitate implementation in future courses.

The media industry has during the last decade migrated services from dedicated medianetworks to more shared resources and lately also the public internet and public data centers. Inorder to cater for such transition, several protocols have been designed to meet the demand forhigh-quality media transport over lossy infrastructure, protocols such as SRT and RIST. Thepurpose of Reliable Internet Stream Transport (RIST) and Secure Reliable Transport (SRT) is tohave all vendors of broadcasting equipment support an interoperable way of communication. Thelack of interoperability locks consumers into one particular vendor’s family of products - most oftenthis equipment only supports a proprietary technology. Interoperability creates a more competitivemarket space which benefits consumers and gives vendors an incentive to be more innovative intheir solutions. The purpose of this thesis is to assess the performance of these protocols by comparing theirperformance to a proprietary solution (named ÖÖÖ in this thesis and seen as an establishedsolution in the industry). The challenge is to test these protocols in a lab environment, but have theresults represent real-world use. For this, a large subset of samples is needed along with samplesmeasured over a long period. This sampling was made possible by writing a script which automatesthe sampling process. The results indicate that the versions of RIST and SRT tested in this thesis to some extentcompare well to the selected established protocol (ÖÖÖ). In many scenarios, SRT even did muchbetter, mainly when a line with a single feed was tested. For instance, when the network suffered a2% drop rate and utilized retransmission SRT performed the best and was the only protocol whichhad some samples where no packets were dropped during one hour of measurements. Whenrunning all three protocols at the same time, SRT also did the best in a network with up to 12% droprate. The results in this thesis should give a broadcaster an idea of which of these protocols willfulfill their requirements in a broadcast application. / I mediabranschen finns det en efterfrågan på utrustning som har inslag av interoperabilitet.Anledningen till detta är att någon som köper produkter från en viss återförsäljare inte vill låsas in idenna återförsäljares ”ekosystem” i flera år framöver. Då en studio sällan uppgraderar hela sinproduktionskedja på samma gång ger interoperabilitet möjligheten att köpa utrustning från andraåterförsäljare när man ska uppgradera något i produktionslinan. Detta leder till en merkonkurrenskraftig marknad samt ger incentiv till nya innovativa lösningar. Detta examensarbete går ut på att utvärdera lösningar som tagits fram för att främjainteroperabilitet och jämföra dem med en existerande proprietärlösning. Reliable Internet StreamTransport (RIST) och Secure Reliable Transport (SRT) är två protokoll som tagits fram för just dettasyfte. Utmaningen med att utvärdera dessa protokoll är att i en labbmiljö få resultat som reflekteraranvändandet av protokollen i verkligheten. Detta har gjorts med hjälp av ett program som tagitsfram i detta examensarbete. Med detta program har testandet kunnat automatiseras. Resultaten i detta examensarbete visar potential hos båda RIST och SRT. SRT är i vissascenarion till och med bättre än den proprietära lösningen. Protokollen visar något buggigtbeteende i vissa instanser, såsom att i vissa fal sluta fungera och inte kunna återgå till normalfunktion utan manuell interaktion. Allt som allt är dock protokollen i de flesta fallen testade i dettaexamensarbete ett godtyckligt alternativ till den jämförda proprietära lösningen.

Distributed Real-Time Media Processing refers to classes of highly distributed, delay no-tolerant applications that account for the majority of the data traffic generated in the world today. Real-Time audio/video conferencing and live content streaming are of particular research interests as technology forecasts predict video traffic surpassing every other type of data traffic in the world in the near future. Live streaming refers to applications in which audio/video streams from a source need to be delivered to a set of geo-distributed destinations while maintaining low latency of stream delivery. Real-time conferencing platforms are application platforms that implement many-to-many audio/video real-time communications. Both of these categories exhibit high sensitivity to both network state (latency, jitter, packet loss, bit rate) as well as stream processing backend load profiles (latency and jitter introduced as Cloud processing of media packets). This thesis addresses enhancing real-time media processing both at the network level parameters as well as Cloud optimisations. We provide a novel, bandwidth management algorithm, for cloud services sharing the same network infrastructure, which provides a 2x improvement in system stability. Further examining network impact on cloud services, we provide a novel hybrid Cloud-Network distributed Cloud architecture to enable locality aware, application enhancements. This architecture led to a multi-cloud management overlay algorithm that maintains low management overhead on large scale cloud deployments. On the application level we provide a study of Media Quality parameters for a WebRTC enabled Media Cloud back-end, and provide patterns of quality metrics with respect to back-end stream load and network parameters. Additionally we empirically show that a "minimal load" algorithm for stream allocation, outperforms other Rotational, or Static Threshold based algorithms. / El procesamiento de medios en tiempo real distribuido se refiere a clases de aplicaciones altamente distribuidas,no tolerantes al retardo, que representan la mayoría del tráfico de datos generado en el mundo actual. Las conferenciasde audio y video en tiempo real y la transmisión de contenido en vivo tienen especial interés en investigación, ya quela prospectiva tecnológica estima que el tráfico de video supere a cualquier otro tipo de tráfico de datos en el futurocercano. La transmisión envivo se refiere a aplicaciones en las que flujos de audio/vídeo de una fuente se han de entregara un conjunto de destinos en lugares geográficos diferentes mientras se mantiene baja la latencia de entrega del flujo(como por ejemplo la cobertura de eventos en vivo). Las plataformas de conferencia en tiempo real son plataformasde  aplicación  que  implementan  comunicaciones  de  audio/video  en  tiempo  real  entre  muchos  participantes.  Ambascategorías presentan una alta sensibilidad tanto al estado de la red (latencia, jitter, pérdida de paquetes, velocidad debits) como a los perfiles de carga de la infraestructura de procesamiento de flujo (latencia y jitter introducidos duranteel procesamiento en la nube de paquetes de datos multimedia). Esta tesis trata de mejorar el procesamiento de datosmultimedia en tiempo real tanto en los parámetros de nivel de red como en las optimizaciones en la nube.En este contexto, investigamos si los recursos de la red se podían controlar a nivel de servicio para aumentar laeficiencia y el rendimiento de la red, así como cuantificar el impacto del recurso compartido de la red en la calidad delservicio. Los recursos de red compartidos afectan el rendimiento del servicio en la nube y, por lo tanto, optimizandoo intercambiando recursos de red pueden mejorar el rendimiento del servicio en la nube. Esta posible degradación delrendimiento se debe a la infraestructura de red compartida no regulada (la asignación de recursos de ancho de banda noes consciente de los objetivos del acuerdo de nivel de servicio (SLO) y de comportamiento). Gestionando el ancho debanda de la red a través de control predictivo, permitimos un mejor uso de los recursos de red disponibles y menoresviolaciones de SLO, logrando una mayor estabilidad del sistema por al menos un factor de 2.Las redes de acceso (AN) (extremo, red principal) de los ISP, transportistas y redes comunitarias no tienen unainfraestructura de nube de propósito general, mientras que los proveedores de recursos de Internet proporcionan bajodemanda recursos de la nube. Encontramos una oportunidad para la unificación de los recursos dentro de un AN y fueracon el fin de proporcionar una oferta de nube unificada a través de una federación de nubes y proporcionar movilidad delservicio hacia los usuarios para optimizar la localidad. Este trabajo de investigación proporciona una nueva arquitecturade red híbrida y nube federada que proporciona una infraestructura de red extendida con un despliegue en nube a granescala, incorporándolo directamente a la infraestructura de red. La nueva arquitectura multi-nube permite a los serviciosllegar a un compromiso entre localidad respecto al usuario o el rendimiento en tiempo de ejecución optimizando asípara latencia para conseguir la asignación óptima de recursos de aplicaciones en tiempo real. Para  optimizar  la  latencia  en  las  aplicaciones  de  transmisión  en  vivo  se  propuso  un  nuevo  algoritmo  desuperposición  de  multi-nube  autogestionado  basado  en  una  topología  de  gradiente  en  la  que  cada  nube  de  unaaplicación de transmisión de flujos optimiza la proximidad del cliente a la fuente. El modelo de aplicación se separa enun  diseño  de  dos  capas,  el  back-end  de  entrega  multi-nube  y  los  clientes  de  flujo.  El  backend  de  gradienteautorregulado minimiza la carga de tráfico creando un árbol de expansión mínimo a través de las nubes que se utilizapara  el  enrutamiento  de  cada  flujo.  El  algoritmo  propuesto  tiene  una  tasa  de  convergencia  muy  rápida  en  losdespliegues de nube a gran escala, y no resulta afectado por la rotación de recursos de la nube, así como proporcionauna mayor estabilidad de la transmisión en vivo.En este trabajo ofrecemos un análisis de calidad de los medios de comunicación y mejoras de los emisores deflujo en la nube en tiempo real, así como estrategias de asignación para mejorar el rendimiento de nivel de serviciode las plataformas de comunicación de Web en tiempo real. Los patrones de calidad de los medios están fuertementeinfluenciados por el rendimiento del procesamiento en la nube, y por lo tanto, al ajustar este aspecto, podemos controlarla calidad de los medios. En particular, demostramos empíricamente que a medida que los tamaños de sesión aumentan,la difusión simultánea supera la codificación de capa única. Además, introducimos un algoritmo de asignación de flujopara minimizar los picos de carga en los retransmisores de flujos en la nube y comparamos el comportamiento devarias políticas de asignación de flujos. Con la mínima información y el requisito de asignación de sesión de un únicoservidor, la política de asignación de carga mínima se comporta bastante mejor que otros algoritmos basados en unumbral rotativo o estático. / Distribuerad realtidshantering av mediadata syftar på klasser av starkt distribuerade tillämpningar som inte tolererar fördröjningar, och som utgör majoriteten av datatrafiken som genereras i världen idag. Audio/video-konferenser i realtid och överföring av innehåll "live" är av speciellt intresse för forskningen eftersom teknikprognoser förutser att videotrafiken kommer att kraftigt dominera över all annan datatrafik i den nära framtiden. "Live streaming" syftar på tillämpningar i vilka audio/video strömmar från en källa och behöver distribueras till en mängd av geografisk distribuerade destinationer medan överföringen bibehåller låg latens i leveransen av det strömmade datat (som ett exempel kan nämnas "live"-täckning av händelser). Konferensplattformar för realtidsdata är tillämpningsplattformar som implementerar realtidskommunikation av audio/video-data av typen "många-till-många". Båda dessa kategorier uppvisar hög känslighet för såväl nätverkets tillstånd (latens, jitter, paketförluster, bithastighet) och lastprofiler av ström bearbetning "back-end" (latens och jitter introducerat som Cloud-hantering av mediadatapaket). Denna avhandling adresserar förbättringar inom realtidshantering av mediainnehåll både med avseende på nätverksnivåns parametrar och optimeraringar för molninfrastrukturen. I detta sammanhang har vi undersökt huruvida nätverksresurserna kan kontrolleras på servicenivån i syfte att öka nätverkets effektivitet och prestanda, och även att kvantifiera påverkan av den delade nätverksresursen på servicekvaliteten. Delade nätverksresurser påverkar molntjänstens prestanda och dessa kan genom en optimering eller handel med nätverksresurser förbättra molntjänstens prestanda. Denna potentiella prestandadegradering beror på en oreglerad delad nätverksinfrastruktur (allokeringen av bandbredd är inte medveten om prestanda och mål för servicenivån). Genom att mediera nätverkets bandbredd genom prediktiv kontroll, möjliggör vi ett bättre utnyttjande av de tillgängliga nätverksresurserna och en lägre grad av avvikelser mot SLO, vilket leder till en ökad stabilitet med åtminstone en faktor 2. Accessnätverken (AN) (edge, kärnnätverk) hos ISP, bärare och lokala nätverk har ingen generell molninfrastruktur, medan s.k. "Internet Resource Providers" erbjuder resurser för molntjänster "on demand". Vi ser en möjlighet till ensande av resurserna inuti ett AN och utanför i syfte att erbjuda ett samlat molntjänsterbjudande genom s.k. "Cloud Federation" och erbjuder tjänstemobilitet för användarna för att optimera lokaliteten. Denna forskningansats erbjuder ett nytt hybrid nätverk med Federated Cloud arkitektur vilken ger en utvidgad nätverksinfrastruktur med en storskalig användning av molntjänster, som direkt inkorporerar denna i nätverksinfrastrukturen. Den nyskapande "Multi-Cloud"-arkitekturen möjliggör för tjänster att balansera lokalitet för användaren mot run-time-prestanda och därigenom optimera för latens mot optimal resursallokering för realtidstillämpningar. För att optimera latensen i "live streaming"-tillämpningar föreslås en nyskapande självstyrd "multi-Cloud-overlay"-algorithm baserad på gradienttopologi i vilken varje moln för en tillämpning inom "stream broadcasting" optimerar klientens närhet till källan. Tillämpningsmodellen separeras i en tvålagersdesign, "multi-cloud delivery back-end" och "stream clients". Denna självreglerande gradientbaserade "back-end" minimerar trafiklasten genom att skapa ett minimalt spännande träd genom molnen som används för routing av strömmarna. Den föreslagna algoritmen har en mycket snabb konvergenshastighet vid större moln, och påverkas inte av "churn" hos molnresursen liksom att den erbjuder ökad motståndskraft hos "live"-strömmen. I detta arbete erbjuder vi mediakvalitetsanalys och förstärkning av realtidsmolnets "forwarders", liksom även allokeringsstrategier för att förstärka servicenivåprestanda hos "Web Real-Time Communication"-plattformar. Mediakvalitetsmönster påverkas kraftigt av molnets bearbetsningsprestanda, och således kan vi genom att påverka denna aspekt kontrollera mediakvaliteten. Specifikt demonstrerar vi empiriskt att efterhand som sessionsstorlekarna ökar, så utklassar simulcast enlagersinkodning. Dessutom introducerar vi en strömallokeringsalgoritm för att minimera "load spikes" hos "Cloud stream forwarders" och jämför beteendet hos olika strömallokeringspolicys. Med enbart minimal information och allokeringsbehoven hos en enskild serversession beter sig den minimala lastbalansallokeringspolicyn tydligt bättre än andra "rotational"- eller "static threshold"-baserade algoritmer. / <p>QC 20170425</p>