An experimental study of client-side Spotify peering behaviour

Spotify is a popular music-streaming service which has seen widespread use across Europe. While Spotify’s server-side behaviour has previously been studied, little is known about the client-side behaviour. In this paper, we describe an experimental study where we collect packet headers for Spotify traffic over multiple 24-hour time frames at a client host. Two distinct types of behaviour are observed, when tracks are being downloaded, and when the client is only serving requests from other peers. We also note wide variation in connection lifetimes, as seen in other studies of peer-to-peer systems. These findings are relevant for improving Spotify itself, and for the designers of other hybrid peer-to-peer and server-based distribution architectures

Converging an Overlay Network to a Gradient Topology

In this paper, we investigate the topology convergence problem for the gossip-based Gradient overlay network. In an overlay network where each node has a local utility value, a Gradient overlay network is characterized by the properties that each node has a set of neighbors with the same utility value (a similar view) and a set of neighbors containing higher utility values (gradient neighbor set), such that paths of increasing utilities emerge in the network topology. The Gradient overlay network is built using gossiping and a preference function that samples from nodes using a uniform random peer sampling service. We analyze it using tools from matrix analysis, and we prove both the necessary and sufficient conditions for convergence to a complete gradient structure, as well as estimating the convergence time and providing bounds on worst-case convergence time. Finally, we show in simulations the potential of the Gradient overlay, by building a more efficient live-streaming peer-to-peer (P2P) system than one built using uniform random peer sampling.Comment: Submitted to 50th IEEE Conference on Decision and Control (CDC 2011

Streaming media over the Internet: Flow based analysis in live access networks

Multimedia service delivery over the Internet is a success. The number of services available and the number of people accessing them is huge. In this paper, we investigate multimedia streaming services over the Internet. Our analysis is based on traffic measurement in live access fiber-to-the-home networks. We study parameters like traffic volume and flow characteristics for selected services. Especially the Swedish P2P video service Voddler and the Swedish P2P music service Spotify are studied. We show that indeed these services are widely used (20% of local hosts using Voddler, 65 % of local hosts using Spotify). We also show that they are different concerning the flow characteristics, with many short flows for Voddler and longer flows for Spotify. One thing that they have in common in our measurements is that the outbound, or uplink, traffic volume is larger than the inbound

Performance challenges of decentralised services

Decentralised, peer-to-peer based services present a variety of security and privacy benefits for their users, and highly scalable to cater for a growing numbers of users, without extra servers being required of the service operator. This presents a significant advantage for newly emerging mobile applications (with high numbers of users, and limited funds for infrastructure), although performance is a challenge when accessing decentralised services. In this paper, we firstly show the performance of our implementation of a decentralised chunk-based storage platform is constrained by the network. We show the impact of network latency on the performance of this decentralised storage solution, and propose our solution to this, in the form of a federated, intermediary server, thus creating a hybrid decentralised service. This approach offers relatively constant performance as latency increases, due to the use of TCP connectivity, while ensuring the advantages of the decentralised service are not lost in the process

Building a scalable index and a web search engine for music on the Internet using Open Source software

The Internet has made possible the access to thousands of freely available music tracks with Creative Commons or Public Domain licenses. Actually, this number keeps growing every year. In practical terms, it is very difficult to browse this music collection, because it is wide and disperse in hundreds of websites. To address the music recommendation issue, a case study on existing systems was made, to put the problem in context in order to identify necessary building blocks. This thesis is mainly focused on the problem of indexing this large collection of music. The reason to focus on this problem, is that there is no database or index holding information about this music material, thus making this research on the subject extremely difficult. In order to figure out what software could help solve this problem, the state of the art in “Open Source tools for web crawling and indexing” was assessed. Based on the conclusions from the state of the art, a prototype was developed and implemented using the most appropriate software framework. The created solution proved it was capable of crawling the web pages, while parsing and indexing MP3 files. The produced index is available through a web search engine interface also producing results in XML format. The results obtained lead to the conclusion that it is attainable to build a scalable index and web search engine for music in the Internet using Open Source software. This is supported by the proof of concept achieved with the working prototype.A Internet tornou possível o acesso a milhares de faixas musicais disponíveis gratuitamente segundo uma licença Creative Commons ou de Domínio Público. Na realidade, este número continua a aumentar em cada ano. Em termos práticos, é muito difícil navegar nesta colecção de música, pois a mesma é vasta e encontra-se dispersa em milhares de sites na Web. Para abordar o assunto da recomendação de música, um caso de estudo sobre sistemas de recomendação de música existentes foi elaborado, para contextualizar o problema e identificar os grandes blocos que os constituem. Esta tese foca-se na problemática da indexação de uma grande colecção de música, pela razão de que, não existe uma base de dados ou índice que contenha informação sobre este repositório musical, tornando muito difícil o estudo nesta matéria. De forma a compreender que software poderia ajudar a resolver o problema, foi avaliado o estado da arte em ferramentas de rastreio de conteúdos web e indexação de código aberto. Com base nas conclusões do estado da arte, o protótipo foi desenvolvido e implementado, utilizando o software mais apropriado para a tarefa. A solução criada provou que era possível percorrer as páginas Web, enquanto se analisavam e indexavam MP3. O índice produzido encontra-se disponível através de um motor de busca online e também com resultados no formato XML. Os resultados obtidos levam a concluir que é possível, construir um índice escalável e motor de busca na web para música na Internet utilizando software Open Source. Estes resultados são fundamentados pela prova de conceito obtida com o protótipo funcional

Static Web content distribution and request routing in a P2P overlay

The significance of collaboration over the Internet has become a corner-stone of modern computing, as the essence of information processing and content management has shifted to networked and Webbased systems. As a result, the effective and reliable access to networked resources has become a critical commodity in any modern infrastructure. In order to cope with the limitations introduced by the traditional client-server networking model, most of the popular Web-based services have employed separate Content Delivery Networks (CDN) to distribute the server-side resource consumption. Since the Web applications are often latency-critical, the CDNs are additionally being adopted for optimizing the content delivery latencies perceived by the Web clients. Because of the prevalent connection model, the Web content delivery has grown to a notable industry. The rapid growth in the amount of mobile devices further contributes to the amount of resources required from the originating server, as the content is also accessible on the go. While the Web has become one of the most utilized sources of information and digital content, the openness of the Internet is simultaneously being reduced by organizations and governments preventing access to any undesired resources. The access to information may be regulated or altered to suit any political interests or organizational benefits, thus conflicting with the initial design principle of an unrestricted and independent information network. This thesis contributes to the development of more efficient and open Internet by combining a feasibility study and a preliminary design of a peer-to-peer based Web content distribution and request routing mechanism. The suggested design addresses both the challenges related to effectiveness of current client-server networking model and the openness of information distributed over the Internet. Based on the properties of existing peer-to-peer implementations, the suggested overlay design is intended to provide low-latency access to any Web content without sacrificing the end-user privacy. The overlay is additionally designed to increase the cost of censorship by forcing a successful blockade to isolate the censored network from the rest of the Internet

Digital disruption in the recording industry

With the rise of peer-to-peer software like Napster, many predicted that the digitalisation, sharing and dematerialisation of music would bring a radical transformation within the recording industry. This opened up a period of controversy and uncertainty in which competing visions were articulated of technology-induced change, markedly polarised between utopian and dystopian accounts with no clear view of ways forwards. A series of moves followed as various players sought to valorise music on the digital music networks, culminating in an emergence of successful streaming services. This thesis examines why there was a mismatch between initial predictions and what has actually happened in the market. It offers a detailed examination of the innovation processes through which digital technology was implemented and domesticated in the recording industry. This reveals a complex, contradictory and constantly evolving landscape in which the development of digital music distribution was far removed from the smooth development trajectories envisaged by those who saw these developments as following a simple trajectory shaped by technical or economic determinants. The research is based upon qualitative data analysis of fifty five interviews with a wide range of entrepreneurs and innovators, focusing on two successful innovation cases with different points of insertion within the digital recording industry; (1) Spotify: currently the world’s most popular digital music streaming service; and (2) INgrooves: an independent digital music distribution service provider whose system is also used by Universal Music Group. The thesis applies perspectives from the Social Shaping of Technology (“SST”) and its extension into Social Learning in Technological Innovation. It explores the widely dispersed processes of innovation through which the complex set of interactions amongst heterogeneous players who have conflicting interests and differing commitments involved in the digital music networks guided diverging choices in relation to particular market conditions and user requirements. The thesis makes three major contributions to understanding digital disruption in the recording industry. (1) In contrast to prevailing approaches which take P2P distribution as the single point of focus, the study investigates the multiplicity of actors and sites of innovation in the digital recording industry. It demonstrates that the dematerialisation of music did not lead to a simple, e.g. technologically-driven transformation of the industry. Instead a diverse array of realignments had to take place across the music sector to develop digital music valorisation networks. (2) By examining the detailed processes involved in the evolution of digital music services, it highlights the ways in which business models are shaped through a learning process of matching and finding constantly changing digital music users’ needs. Based on the observation that business models must be discovered in the course of making technologies work in the market, a new framework of ‘social shaping of business models’ is proposed in order to conceptualise business models as an emergent process in which firms refine their strategies in the light of emerging circumstances. (3) Drawing upon the concepts of musical networks (Leyshon 2001) and mediation (Hennion 1989), the thesis investigates the interaction of the diverse actors across the circuit of the recording business – production, distribution, valorisation, and consumption. The comprehensive analysis of the intricate interplay between innovation actors and their interactions in the economic, cultural, legal and institutional context highlights the need to develop a more sophisticated and nuanced understanding of the recording industry