<p>In recent years, with the fast development of resource capability of both the Internet and personal computers, multimedia applications like video-on-demand (VOD) streaming have gained dramatic growth and been shown to be potential killer applications in the current and next-generation Internet. Scalable deployment of these applications has become a hot problem area due to the potentially high server and network bandwidth required in these systems.</p><p>The conventional approach in a VOD streaming system dedicates a media stream for each client request, which is not scalable in a wide-area delivery system serving potentially very large numbers of clients. Recently, various efficient delivery techniques have been proposed to improve the scalability of VOD delivery systems. One approach is to use a scalable delivery protocol based on multicast, such as periodic broadcast or stream merging. These protocols have been mostly developed for single-server based systems and attempt to have each media stream serve as many clients as possible, so as to minimize the required server and network bandwidth. However, the performance improvements possible with techniques that deliver all streams from a single server are limited, especially regarding the required network bandwidth. Another approach is based on proxy caching and content replication, such as in content delivery networks (CDN). Although this approach is able to effectively distribute load across multiple CDN servers, the cost of this approach may be high.</p><p>With the focus on further improving the system efficiency regarding the server and network bandwidth requirement, a new scalable streaming protocol is developed in this work. It adapts a previously proposed technique called hierarchical multicast stream merging (HMSM) to use a peer-to-peer delivery approach. To be more efficient in media delivery, the conventional early merging policy associated with HMSM is extended to be compatible with the peer-to-peer environment, and various peer selection policies are designed for initiation of media streams. The impact of limited peer resource capability is also studied in this work. In the performance study, a number of simulation experiments are conducted to evaluate the performance of the new protocol and various design policies, and promising results are reported.

Peer-assisted Video-on-Demand (VoD) systems have not only received substantial recent research attention, but also been implemented and deployed with success in large-scale real-world streaming systems. Despite the remarkable popularity in real-world systems, the design of such systems are not well understood. In this thesis, we seek to address two design problems in peer-assisted VoD systems. First, we focus on the design of cache replacement algorithms. We construct an analytical framework based on dynamic programming, to help us form an in-depth understanding of optimal strategies to design cache replacement algorithms. Second, we shift our attention to the surplus upload bandwidth allocation problem in multi-channel systems. Through theoretical analysis and realistic simulations, we conclude that surplus upload bandwidth from peers can be utilized more efficiently than conventional prefetching strategies when it is devoted to redistributing content to those channels in deficit state.

Peer-assisted Video-on-Demand (VoD) systems have not only received substantial recent research attention, but also been implemented and deployed with success in large-scale real-world streaming systems. Despite the remarkable popularity in real-world systems, the design of such systems are not well understood. In this thesis, we seek to address two design problems in peer-assisted VoD systems. First, we focus on the design of cache replacement algorithms. We construct an analytical framework based on dynamic programming, to help us form an in-depth understanding of optimal strategies to design cache replacement algorithms. Second, we shift our attention to the surplus upload bandwidth allocation problem in multi-channel systems. Through theoretical analysis and realistic simulations, we conclude that surplus upload bandwidth from peers can be utilized more efficiently than conventional prefetching strategies when it is devoted to redistributing content to those channels in deficit state.

The Service Oriented Architecture (SOA) is emerging as a new standard for building large loosely coupled systems. Web Services, the dominant implementation platform for SOA, use a server-centric approach to manage all components. This limits the deployment of Web Services to static domains, since a service invocation will fail if the server component changes its availability or location. <p>This research focuses on the possibilities of integrating P2P technology into the Web Services environment as a means of increasing its robustness. A P2P-Web Services architecture is presented that enables service discovery and service invocations in dynamic environments. The corresponding experiments on the reference system and the simulation system present the characteristics and improvements of the hybrid system.

Peer-to-Peer (P2P) refers to a class of systems and/or applications that use distributed resources in a decentralized and autonomous manner to achieve a goal. A number of successful applications, like BitTorrent (for file and content sharing) and SETI@Home (for distributed computing) have demonstrated the feasibility of this approach. <p> As a new form of distributed computing, P2P computing has the same coordination problems as other forms of distributed computing. Coordination has been considered an important issue in distributed computing for a long time and many coordination models and languages have been developed. <p> This research focuses on how to solve coordination problems in P2P computing. In particular, it is to provide a seamless P2P computing environment so that the migration of computation components is transparent. This research extends Manifold, an event-driven coordination model, to meet P2P computing requirements and integrates the P2P-Manifold model into an existing platform. The integration hides the complexity of the coordination model and makes the model easy to use.

Peer-to-peer (P2P) systems are a relatively new addition to the large area of distributed computer systems. The emphasis on sharing resources, self-organization and use of discovery mechanisms sets the P2P systems apart from other forms of distributed computing. <p> Project JXTA is the first P2P application development platform, consisting of standard protocols, programming tools and multi-language implementations. A JXTA peer network is a complex overlay, constructed on top of the physical network, with its own identification scheme and routing. <p> This thesis investigates the performance of JXTA using benchmarking. The presented work includes the development of the JXTA Performance Model and Benchmark Suite, as well as the collection and analysis of the performance results. By evaluating three major versions of the protocol implementations in a variety of configurations, the performance characteristics, limitations, bottlenecks and trade-offs are observed and discussed. <p> It is shown that the complexity of JXTA allows many factors to affect its performance and that several JXTA components exhibit unintuitive and unexpected behavior. However, the results also reveal the ways to maximize the performance of the deployed and newly designed systems. <p>The evolution of JXTA through several versions shows some notable improvements, especially in search and discovery models and added messaging components, which make JXTA a promising member of the future generation of computer systems.

Peer-to-peer (P2P) systems are a relatively new addition to the large area of distributed computer systems. The emphasis on sharing resources, self-organization and use of discovery mechanisms sets the P2P systems apart from other forms of distributed computing. <p> Project JXTA is the first P2P application development platform, consisting of standard protocols, programming tools and multi-language implementations. A JXTA peer network is a complex overlay, constructed on top of the physical network, with its own identification scheme and routing. <p> This thesis investigates the performance of JXTA using benchmarking. The presented work includes the development of the JXTA Performance Model and Benchmark Suite, as well as the collection and analysis of the performance results. By evaluating three major versions of the protocol implementations in a variety of configurations, the performance characteristics, limitations, bottlenecks and trade-offs are observed and discussed. <p> It is shown that the complexity of JXTA allows many factors to affect its performance and that several JXTA components exhibit unintuitive and unexpected behavior. However, the results also reveal the ways to maximize the performance of the deployed and newly designed systems. <p>The evolution of JXTA through several versions shows some notable improvements, especially in search and discovery models and added messaging components, which make JXTA a promising member of the future generation of computer systems.

Peer-to-Peer (P2P) refers to a class of systems and/or applications that use distributed resources in a decentralized and autonomous manner to achieve a goal. A number of successful applications, like BitTorrent (for file and content sharing) and SETI@Home (for distributed computing) have demonstrated the feasibility of this approach. <p> As a new form of distributed computing, P2P computing has the same coordination problems as other forms of distributed computing. Coordination has been considered an important issue in distributed computing for a long time and many coordination models and languages have been developed. <p> This research focuses on how to solve coordination problems in P2P computing. In particular, it is to provide a seamless P2P computing environment so that the migration of computation components is transparent. This research extends Manifold, an event-driven coordination model, to meet P2P computing requirements and integrates the P2P-Manifold model into an existing platform. The integration hides the complexity of the coordination model and makes the model easy to use.

The objective of this project is to improve the performance of the Gnutella peer-to-peer protocol (version 0.4) by introducing a semantic-social routing model and several categories of interest. The Gnutella protocol requires peers to broadcast messages to their neighbours when they search files. The message passing generates a lot of traffic in the network, which degrades the quality of service. We propose using social networks to optimize the speed of search and to improve the quality of service in a Gnutella based peer-to-peer environment. Each peer creates and updates a friends list from its past experience, for each category of interest. Once peers generate their friends lists, they use these lists to semantically route queries in the network. Search messages in a given category are mainly sent to friends who have been useful in the past in finding files in the same category. This helps to reduce the search time and to decrease the network traffic by minimizing the number of messages circulating in the system as compared to standard Gnutella. This project will demonstrate by simulating a peer-to-peer type of environment with the JADE multi-agent system platform that by learning other peers interests, building and exploiting their social networks (friends lists) to route queries semantically, peers can get more relevant resources faster and with less traffic generated, i.e. that the performance of the Gnutella system can be improved.

The Service Oriented Architecture (SOA) is emerging as a new standard for building large loosely coupled systems. Web Services, the dominant implementation platform for SOA, use a server-centric approach to manage all components. This limits the deployment of Web Services to static domains, since a service invocation will fail if the server component changes its availability or location. <p>This research focuses on the possibilities of integrating P2P technology into the Web Services environment as a means of increasing its robustness. A P2P-Web Services architecture is presented that enables service discovery and service invocations in dynamic environments. The corresponding experiments on the reference system and the simulation system present the characteristics and improvements of the hybrid system.