Performance Analysis of Publish/Subscribe Systems

The Desktop Grid offers solutions to overcome several challenges and to answer increasingly needs of scientific computing. Its technology consists mainly in exploiting resources, geographically dispersed, to treat complex applications needing big power of calculation and/or important storage capacity. However, as resources number increases, the need for scalability, self-organisation, dynamic reconfigurations, decentralisation and performance becomes more and more essential. Since such properties are exhibited by P2P systems, the convergence of grid computing and P2P computing seems natural. In this context, this paper evaluates the scalability and performance of P2P tools for discovering and registering services. Three protocols are used for this purpose: Bonjour, Avahi and Free-Pastry. We have studied the behaviour of theses protocols related to two criteria: the elapsed time for registrations services and the needed time to discover new services. Our aim is to analyse these results in order to choose the best protocol we can use in order to create a decentralised middleware for desktop grid

Developments in Practice VI: Riding the Wave: Discovering the Value of P2P Technologies

Peer-to-peer (P2P) gurus suggest that inexpensive computing power, bandwidth, and storage will enable radically new enterprise forms that are driven by the distribution of interactive computing power more or less equally through the enterprise. Based on the capabilities of the Internet (as opposed to the web), which forms a vast network of computers that can be linked in many different ways, P2P has been called a third age in Internet time and the next logical evolution of the Internet . While such predictions may be somewhat hyper-optimistic, the speed with which this technology already spread from underground to mainstream is remarkable. Whether they like it or not, companies will soon need to determine how they are going to deal with P2P, just as they did with other major technology shifts (e.g., PCs, e-commerce). This paper is designed to help researchers and managers understand the challenges P2P technology poses for CIOs and organizations. It first gives an overview of these technologies, including their current status, probable applications and the opportunities and challenges involved in using them. Then, it discusses the strategic potential of P2P for organizations and explores some of the areas in which P2P could have a significant impact on how business and IT functions work. It concludes with some advice to CIOs about how to begin integrating P2P into their organization and some suggestions for researching the impacts of this technology on business

A schema-based P2P network to enable publish-subscribe for multimedia content in open hypermedia systems

Open Hypermedia Systems (OHS) aim to provide efficient dissemination, adaptation and integration of hyperlinked multimedia resources. Content available in Peer-to-Peer (P2P) networks could add significant value to OHS provided that challenges for efficient discovery and prompt delivery of rich and up-to-date content are successfully addressed. This paper proposes an architecture that enables the operation of OHS over a P2P overlay network of OHS servers based on semantic annotation of (a) peer OHS servers and of (b) multimedia resources that can be obtained through the link services of the OHS. The architecture provides efficient resource discovery. Semantic query-based subscriptions over this P2P network can enable access to up-to-date content, while caching at certain peers enables prompt delivery of multimedia content. Advanced query resolution techniques are employed to match different parts of subscription queries (subqueries). These subscriptions can be shared among different interested peers, thus increasing the efficiency of multimedia content dissemination

Peer-to-peer and community-based markets: A comprehensive review

The advent of more proactive consumers, the so-called "prosumers", with production and storage capabilities, is empowering the consumers and bringing new opportunities and challenges to the operation of power systems in a market environment. Recently, a novel proposal for the design and operation of electricity markets has emerged: these so-called peer-to-peer (P2P) electricity markets conceptually allow the prosumers to directly share their electrical energy and investment. Such P2P markets rely on a consumer-centric and bottom-up perspective by giving the opportunity to consumers to freely choose the way they are to source their electric energy. A community can also be formed by prosumers who want to collaborate, or in terms of operational energy management. This paper contributes with an overview of these new P2P markets that starts with the motivation, challenges, market designs moving to the potential future developments in this field, providing recommendations while considering a test-case