Content Distribution in P2P Systems

The report provides a literature review of the state-of-the-art for content distribution. The report's contributions are of threefold. First, it gives more insight into traditional Content Distribution Networks (CDN), their requirements and open issues. Second, it discusses Peer-to-Peer (P2P) systems as a cheap and scalable alternative for CDN and extracts their design challenges. Finally, it evaluates the existing P2P systems dedicated for content distribution according to the identied requirements and challenges

Location-Aware Index Caching and Searching for P2P Systems

International audienceUnstructured P2P networks remain widely deployed in file-sharing systems, due to their simple features. However, the P2P traffic, mainly composed of repetitive query messages, contributes the largest portion of the Internet traffic. The principal causes of this critical issue are the search inefficiency and the construction of the P2P overlay without any knowledge of the underlying topology. In order to reduce the P2P redundant traffic and to address the limitations of existing solutions, we propose a solution that performs index caching and efficient query routing while supporting keyword search. We aim at improving the probability of finding available copies of requested files by leveraging file replication. In addition, our scheme tries to direct queries to close results, by using topological information in terms of file physical distribution. We believe that the traffic can be reduced and the user experience ameliorated in terms of faster downloads, with minimum overhead

Content Distribution in P2P Systems

The report provides a literature review of the state-of-the-art for content distribution. The report's contributions are of threefold. First, it gives more insight into traditional Content Distribution Networks (CDN), their requirements and open issues. Second, it discusses Peer-to-Peer (P2P) systems as a cheap and scalable alternative for CDN and extracts their design challenges. Finally, it evaluates the existing P2P systems dedicated for content distribution according to the identied requirements and challenges

The Cloud Strikes Back: Investigating the Decentralization of IPFS

Interplanetary Filesystem (IPFS) is one of the largest peer-to-peer filesystems in operation. The network is the default storage layer for Web3 and is being presented as a solution to the centralization of the web. In this paper, we present a large-scale, multi-modal measurement study of the IPFS network. We analyze the topology, the traffic, the content providers and the entry points from the classical Internet. Our measurements show significant centralization in the IPFS network and a high share of nodes hosted in the cloud. We also shed light on the main stakeholders in the ecosystem. We discuss key challenges that might disrupt continuing efforts to decentralize the Web and highlight multiple properties that are creating pressures toward centralization

Locaware: Index Caching in Unstructured P2P-file Sharing Systems

International audienceThough widely deployed for file-sharing, unstructured P2P systems aggressively exploit network resources as they grow in popularity. The P2P traffic is the leading consumer of bandwidth, mainly due to search inefficiency, as well as to large data transfers over long distances. This critical issue may compromise the benefits of such systems by drastically limiting their scalability. In order to reduce the P2P redundant traffic, we propose Locaware, which performs index caching while supporting keyword search. Locaware aims at reducing the network load by directing queries to available nearby results. For this purpose, Locaware leverages natural file replication and uses topological information in terms of file physical distribution

Locaware: Index Caching in Unstructured P2P-file Sharing Systems

International audienceThough widely deployed for file-sharing, unstructured P2P systems aggressively exploit network resources as they grow in popularity. The P2P traffic is the leading consumer of bandwidth, mainly due to search inefficiency, as well as to large data transfers over long distances. This critical issue may compromise the benefits of such systems by drastically limiting their scalability. In order to reduce the P2P redundant traffic, we propose Locaware, which performs index caching while supporting keyword search. Locaware aims at reducing the network load by directing queries to available nearby results. For this purpose, Locaware leverages natural file replication and uses topological information in terms of file physical distribution

Video-on-Demand over Internet: a survey of existing systems and solutions

Video-on-Demand is a service where movies are delivered to distributed users with low delay and free interactivity. The traditional client/server architecture experiences scalability issues to provide video streaming services, so there have been many proposals of systems, mostly based on a peer-to-peer or on a hybrid server/peer-to-peer solution, to solve this issue. This work presents a survey of the currently existing or proposed systems and solutions, based upon a subset of representative systems, and defines selection criteria allowing to classify these systems. These criteria are based on common questions such as, for example, is it video-on-demand or live streaming, is the architecture based on content delivery network, peer-to-peer or both, is the delivery overlay tree-based or mesh-based, is the system push-based or pull-based, single-stream or multi-streams, does it use data coding, and how do the clients choose their peers. Representative systems are briefly described to give a summarized overview of the proposed solutions, and four ones are analyzed in details. Finally, it is attempted to evaluate the most promising solutions for future experiments. Résumé La vidéo à la demande est un service où des films sont fournis à distance aux utilisateurs avec u

RDF Data Indexing and Retrieval: A survey of Peer-to-Peer based solutions

The Semantic Web enables the possibility to model, create and query resources found on the Web. Enabling the full potential of its technologies at the Internet level requires infrastructures that can cope with scalability challenges and support various types of queries. The attractive features of the Peer-to-Peer (P2P) communication model such as decentralization, scalability, fault-tolerance seems to be a natural solution to deal with these challenges. Consequently, the combination of the Semantic Web and the P2P model can be a highly innovative attempt to harness the strengths of both technologies and come up with a scalable infrastructure for RDF data storage and retrieval. In this respect, this survey details the research works that adopt this combination and gives an insight on how to deal with the RDF data at the indexing and querying levels.Le Web Sémantique permet de modéliser, créer et faire des requêtes sur les ressources disponibles sur le Web. Afin de permettre à ses technologies d'exploiter leurs potentiels à l'échelle de l'Internet, il est nécessaire qu'elles reposent sur des infrastructures qui puissent passer à l'échelle ainsi que de répondre aux exigences d'expressivité des types de requêtes qu'elles offrent. Les bonnes propriétés qu'offrent les dernières générations de systèmes pair-à- pair en termes de décentralisation, de tolérance aux pannes ainsi que de passage à l'échelle en font d'eux des candidats prometteurs. La combinaison du modèle pair-à-pair et des technologies du Web Sémantique est une tentative innovante ayant pour but de fournir une infrastructure capable de passer à l'échelle et pouvant stocker et rechercher des données de type RDF. Dans ce contexte, ce rapport présente un état de l'art et discute en détail des travaux autour de systèmes pair-à-pair qui traitent des données de type RDF à large échelle. Nous détaillons leurs mécanismes d'indexation de données ainsi que le traitement des divers types de requêtes offerts

Peer-to-peer multimedia communication

I sistemi Peer-to-Peer (P2P) sono stati inventi, messi in campo e studiati da più di dieci anni, andando al di là della semplice applicazione per scambio di file. Nelle reti P2P i partecipanti si organizzano in una rete "overlay" che è astratta rispetto alle caratteristiche della sottostante rete fisica. Scopo di questi sistemi è la distribuzione di risorse quali contenuti, spazio di memorizzazione o cicli macchina. Gli utenti quindi giocano un ruolo attivo e possono essere considerati come sia clienti che serventi allo stesso tempo per il particolare servizio che la rete P2P offre. Lo scopo di questa tesi di dottorato è lo studio di questi sistemi ed il dare un contributo nella loro analisi prestazionale. L'analisi mira a valutare le prestazioni raggiunte dai sistemi e/o i limiti teorici raggiungibili. Infatti, nonostante esistano diversi meccanismi per il peer-to-peer streaming, l'analisi prestazionale di questo tipo di sistemi può essere considerata ancora nella sua infanzia. A questo scopo, i contributi principali di questa tesi di dottorato sono: i)la derivazione di un limite teorico per il ritardo nei sistemi di P2P streaming, ii) la creazione di un algoritmo che sfrutti le conoscenze acquisite attraverso il lavoro teorico, iii) l'analisi prestazionale dell'algoritmo utilizzando un simulatore espressamente progettato per riprodurre le caratteristiche delle reti P2P reali composte da centinaia di migliaia di nodi che si connettono e disconnettono in continuazione.Peer-to-Peer (P2P) systems have been invented, deployed and researched for more than ten years and went far beyond the simple file sharing applications. In P2P networks, participants organize themselves in an overlay network that abstracts from the topological characteristics of the underlying physical network. Aim of these systems is the distribution of some kind of resources like contents, storage, or CPU cycles. Users, therefore, play an active role so that they can be considered as client and server at the same time, for the particular service that is provided through the P2P paradigm. Goal of this dissertation thesis is to study these systems, and give contributes in their performance evaluation. The analysis will aim to evaluate the achieved performance of a system and/or the performance bounds that could be achievable. In fact, even if there are several proposals of different systems, peer-to-peer streaming performance analysis can be considered still in its infancy and there is still a lot of work to do. To this aim, the main contributes of this dissertation thesis are i) the derivation of a theoretical delay bounds for P2P streaming system ii) II the creation of an algorithm that exploits the new insights that come out from the theoretical study iii) the performance evaluation of this algorithm using an ad-hoc simulator, expressly tailored to reproduce the characteristics of the real-world P2P streaming systems, composed by hundred thousands of intermittently connected users