On Using Seeders for P2P Live Streaming

Seeders (peers that do not request anything but contribute to the system) are a powerful concept in peer-to-peer (P2P). They allow to leverage the capacities of a P2P system. While seeding is a natural idea for filesharing or video-on-demand applications, it seems somehow counter-intuitive in the context of live streaming. This paper aims at describing the feasibility and performance of P2P live seeding. After a formal definition of ''live seeding'' and efficiency, we consider the theoretical performance of systems where the overhead is neglected. We then propose a linear overhead model and extend the results for this model, for a single seeder and for a set of seeders as well (it is not always possible to perfectly aggregate individual efficiencies in a given system).Les semeurs (pairs possédant déjà un contenu donné et contribuant à sa dissémination) sont un concept clé du pair-à-pair (P2P). Ils permettent entre autres d'accroître les performances d'un système P2P. Mais alors qu'il est naturel d'avoir des semeurs dans le contexte du partage de fichiers ou de la vidéo-à-la-demande, cela semble incompatible avec de la diffusion en direct. Le but de ce rapport est de montrer que, dans une certaine mesure, cela est réalisable. Après avoir défini formellement le concept de semeur pour la diffusion en direct, et proposé une définition d'efficacité, nous regardons la performance théorique des semeurs pour des systèmes où le coût de contrôle est négligé. Nous proposons ensuite un modèle avec coût de contrôle affine, et donnons les résultats pour un semeur unique tout comme pour un ensemble de semeurs (un ensemble de semeurs ne se comporte pas nécessairement aussi bien que la somme de ses éléments)

On Using Seeders for P2P Live Streaming

Seeders (peers that do not request anything but contribute to the system) are a powerful concept in peer-to-peer (P2P). They allow to leverage the capacities of a P2P system. While seeding is a natural idea for filesharing or video-on-demand applications, it seems somehow counter-intuitive in the context of live streaming. This paper aims at describing the feasibility and performance of P2P live seeding. After a formal definition of ''live seeding'' and efficiency, we consider the theoretical performance of systems where the overhead is neglected. We then propose a linear overhead model and extend the results for this model, for a single seeder and for a set of seeders as well (it is not always possible to perfectly aggregate individual efficiencies in a given system).Les semeurs (pairs possédant déjà un contenu donné et contribuant à sa dissémination) sont un concept clé du pair-à-pair (P2P). Ils permettent entre autres d'accroître les performances d'un système P2P. Mais alors qu'il est naturel d'avoir des semeurs dans le contexte du partage de fichiers ou de la vidéo-à-la-demande, cela semble incompatible avec de la diffusion en direct. Le but de ce rapport est de montrer que, dans une certaine mesure, cela est réalisable. Après avoir défini formellement le concept de semeur pour la diffusion en direct, et proposé une définition d'efficacité, nous regardons la performance théorique des semeurs pour des systèmes où le coût de contrôle est négligé. Nous proposons ensuite un modèle avec coût de contrôle affine, et donnons les résultats pour un semeur unique tout comme pour un ensemble de semeurs (un ensemble de semeurs ne se comporte pas nécessairement aussi bien que la somme de ses éléments)

AngelCast: cloud-based peer-assisted live streaming using optimized multi-tree construction

Increasingly, commercial content providers (CPs) offer streaming solutions using peer-to-peer (P2P) architectures, which promises significant scalabil- ity by leveraging clients’ upstream capacity. A major limitation of P2P live streaming is that playout rates are constrained by clients’ upstream capac- ities – typically much lower than downstream capacities – which limit the quality of the delivered stream. To leverage P2P architectures without sacri- ficing quality, CPs must commit additional resources to complement clients’ resources. In this work, we propose a cloud-based service AngelCast that enables CPs to complement P2P streaming. By subscribing to AngelCast, a CP is able to deploy extra resources (angel), on-demand from the cloud, to maintain a desirable stream quality. Angels do not download the whole stream, nor are they in possession of it. Rather, angels only relay the minimal fraction of the stream necessary to achieve the desired quality. We provide a lower bound on the minimum angel capacity needed to maintain a desired client bit-rate, and develop a fluid model construction to achieve it. Realizing the limitations of the fluid model construction, we design a practical multi- tree construction that captures the spirit of the optimal construction, and avoids its limitations. We present a prototype implementation of AngelCast, along with experimental results confirming the feasibility of our service.Supported in part by NSF awards #0720604, #0735974, #0820138, #0952145, #1012798 #1012798 #1430145 #1414119. (0720604 - NSF; 0735974 - NSF; 0820138 - NSF; 0952145 - NSF; 1012798 - NSF; 1430145 - NSF; 1414119 - NSF

On the Limit of Fountain MDC Codes for Video Peer-To-Peer Networks

Video streaming for heterogeneous types of devices, where nodes have different devices characteristics in terms of computational capacity and display, is usually handled by encoding the video with different qualities. This is not well suited for Peer-To-Peer (P2P) systems, as a single peer group can only share content of the same quality, thus limiting the peer group size and efficiency. To address this problem, several existing works propose the use of Multiple Descriptions Coding (MDC). The concept of this type of video codec is to split a video in a number of descriptions which can be used on their own, or aggregated to improve the global quality of the video. Unfortunately existing MDC codes are not flexible, as the video is split in a defined number of descriptions. In this paper, we focus on the practical feasibility of using a Fountain MDC code with properties similar to existing Fountain erasure codes, including the ability to create any number of descriptions when needed (on the fly). We perform simulations using selected pictures to assess the feasibility of using these codes, knowing that they should improve the availability of the video pieces in a P2P system and hence the video streaming quality. We observe that, although this idea seems promising, the evaluated benefits, demonstrated by the PSNR values, are limited when used in a real P2P video streaming system

The state of peer-to-peer network simulators

Networking research often relies on simulation in order to test and evaluate new ideas. An important requirement of this process is that results must be reproducible so that other researchers can replicate, validate and extend existing work. We look at the landscape of simulators for research in peer-to-peer (P2P) networks by conducting a survey of a combined total of over 280 papers from before and after 2007 (the year of the last survey in this area), and comment on the large quantity of research using bespoke, closed-source simulators. We propose a set of criteria that P2P simulators should meet, and poll the P2P research community for their agreement. We aim to drive the community towards performing their experiments on simulators that allow for others to validate their results

Mathematical analysis of scheduling policies in peer-to-peer video streaming networks

Las redes de pares son comunidades virtuales autogestionadas, desarrolladas en la capa de aplicación sobre la infraestructura de Internet, donde los usuarios (denominados pares) comparten recursos (ancho de banda, memoria, procesamiento) para alcanzar un fin común. La distribución de video representa la aplicación más desafiante, dadas las limitaciones de ancho de banda. Existen básicamente tres servicios de video. El más simple es la descarga, donde un conjunto de servidores posee el contenido original, y los usuarios deben descargar completamente este contenido previo a su reproducción. Un segundo servicio se denomina video bajo demanda, donde los pares se unen a una red virtual siempre que inicien una solicitud de un contenido de video, e inician una descarga progresiva en línea. El último servicio es video en vivo, donde el contenido de video es generado, distribuido y visualizado simultáneamente. En esta tesis se estudian aspectos de diseño para la distribución de video en vivo y bajo demanda. Se presenta un análisis matemático de estabilidad y capacidad de arquitecturas de distribución bajo demanda híbridas, asistidas por pares. Los pares inician descargas concurrentes de múltiples contenidos, y se desconectan cuando lo desean. Se predice la evolución esperada del sistema asumiendo proceso Poisson de arribos y egresos exponenciales, mediante un modelo determinístico de fluidos. Un sub-modelo de descargas secuenciales (no simultáneas) es globalmente y estructuralmente estable, independientemente de los parámetros de la red. Mediante la Ley de Little se determina el tiempo medio de residencia de usuarios en un sistema bajo demanda secuencial estacionario. Se demuestra teóricamente que la filosofía híbrida de cooperación entre pares siempre desempeña mejor que la tecnología pura basada en cliente-servidor

Black Hole Attack, in P2P based VoD Service, and its Effects on Swarm Sizes and Seeders

From the inception, BitTorrent has been under several types of attacks. Most of these attacks were aimed to deteriorate the performance of BitTorrent network or to collapse it.In this paper we have presented the effect of Black-hole attack especially in the case of BitTorrent based VoD services .we have simulated black-hole attack for BitTorrent based VoD services and studied the effect of number of malicious nodes in peer network of various swarm sizes. The number of attacking nodes taken was 1, 2, and 3 whereas the size of swarms was 10, 20 and 30. Also another important parameter taken into consideration for studying the effect was then total number of seeders. We have taken observation for attack simulations for various scenarios depending upon swarm size, numbers of seeder and number of attack nodes

Study of Negative effects of Traffic Localization

Català: Les xarxes P2P s'han convertit en una important xarxa per usuaris i ISP. Els usuaris volen compartir i aprofitar aquestes noves xarxes. D'altra banda, els ISP no volen que els usuaris utilitzin de manera tan intensa les seves connexions a Internet. Això causa que els seus beneficis es redueixin. La localització de tràfic ha estat anunciat com una solució per als inconvenients del P2P. Redueix el tràfic intercanviat entre els usuaris fent clúster. Només uns pocs usuaris d'un cluster intercanviaren dades amb altres xarxes. Hi ha diversos estudis que mostren els beneficis d'aquesta mesura, però no hi ha massa estudis sobre els efectes negatius. En el nostre treball hem tractat de simular una xarxa BitTorrent. Un cop tinguem aquesta xarxa preparada simularem una xarxa que utilitzi tècniques de localització de trànsit. Fent diverses simulacions volem demostrar com la localització de trànsit afecta l'experiència dels usuaris.Castellano: Las redes P2P se han convertido en una importante red para usuarios e ISP. Los usuarios quieren compartir y aprovechar estas nuevas redes. Por otra parte, los ISP no les interesa que los usuarios utilicen de manera tan intensa sus conexiones. Esto es debido a que sus beneficios se ven reducidos. La localización de tráfico ha sido anunciada como una de las mejores soluciones para los inconvenientes del P2P. Reduce el tráfico intercambiado entre los usuarios lejanos o de diferentes redes haciendo clúster. Sólo unos pocos usuarios de un clúster van a intercambiar datos con otros usuarios de otras redes. Hay varios estudios que indican los beneficios de esta medida, pero no hay demasiados estudios acerca de los efectos negativos. En nuestro trabajo hemos tratado de simular una red BitTorrent. Una vez que tengamos esta red lista simularemos una red P2P con alguna técnica de localización de tráfico. Haciendo varias simulaciones queremos demostrar cómo la localización de tráfico afecta a la experiencia de los usuarios.English: P2P networks has become one important network for users and ISP. Users wants to share and take profit of this new networks. On the other hand, ISP don not want users' to use so intensively their internet connections because their profits are being reduced. Traffic Localization has been announced as a solution for P2P disadvantages. It reduces the traffic exchanged between users making cluster. Only a few users from one cluster are going to change data to other networks. There are several studies that indicates the benefits of this measure but there are not too much studies about negative effects. In our work we tried to simulate a BitTorrent network. Once we have this network ready we constructed it making clusters simulating some Traffic Localization technique. Making several simulations we want to prove how traffic localization affects users' experience