Peer-to-Peer (P2P) streaming systems, such as PPLive, have become a popular service with the widespread deployment of broadband networks. However, P2P streaming systems still face free-riding problems, similar to those that have been observed in P2P file sharing systems. Thus, one important problem in providing streaming services is that of providing appropriate incentives for peers to contribute their upload capacity. To this end, we propose the use of advertisements as an incentive for peers to contribute upload capacity. In the proposed framework, peers enjoy the same quality of streamed media, with the difference in quality of service being achieved through different amounts of advertisements viewed, based on the resource contributions to the system. A simulation-based study is performed, which demonstrates that our approach provides appropriate incentives for peers to contribute their resources.

In recent years a number of research efforts have focused on effective use of P2P-based systems in providing large scale video streaming services. In particular, live streaming and Video-on-Demand (VoD) systems have attracted much interest. While previous efforts mainly focused on the common challenges faced by both types of applications, there are still a number of fundamental open questions in designing P2P-based VoD systems, which is the focus of our effort. Specifically, in this paper, we consider a BitTorrent-like VoD system and focus on the following questions: (1) how the lack of load balance, which typically exists in a P2P- based VoD system, affects the performance and what steps can be taken to remedy that, and (2) is a FCFS approach to serving requests at a peer sufficient or whether a Deadline-Aware Scheduling (DAS) approach can lead to performance improvements. Given the deadline considerations that exist in VoD systems, we also investigate approaches to avoiding unnecessary queueing time. For each of these questions, we first illustrate deficiencies of current approaches in adequately meeting streaming quality of service requirements. Motivated by this, we propose several practical schemes aimed at addressing these questions. To illustrate the benefits of our approach, we present an extensive simulation-based performance study.

Multipath streaming protocols have recently attracted much attention because they provide an effective means to provide high-quality streaming over the Internet. However, many existing schemes require a long start-up delay and thus are not suitable for interactive applications such as video conferencing and tele-presence. In this paper, we focus on real-time live streaming applications with stringent end-to-end latency requirement, say several hundreds of milliseconds. To address these challenges, we take a joint multipath and FEC approach that intelligently splits the FEC-encoded stream among multiple available paths. We develop an analytical model and use asymptotic analysis to derive closed-form, optimal load splitting solutions, which are surprisingly simple yet insightful. To our best knowledge, this is the first work that provides such closed-form optimal solutions. Based on the analytical insights, we have designed and implemented a novel encoded multipath streaming (EMS) scheme for real-time live streaming. EMS strives to continuously satisfy the application's QoS requirements by dynamically adjusting the load splitting decisions and the FEC settings. Our simulation results have shown that EMS can not only outperform the existing multipath streaming schemes, but also adapt to the dynamic loss and delay characteristics of the network with minimal overhead.

Peer-to-peer (P2P) systems in general, and BitTorrent (BT) specifically, have been of significant interest to researchers and Internet users alike. Existing models of BT abstract away certain characteristics of the protocol that are important, which we address in this work. We present a simple yet accurate and easily extensible model of BT. The model's accuracy is validated through a rigorous simulation-based study and its extensibility is illustrated by incorporating recently proposed approaches to protocol changes in BT.

We consider the following basic question: a source node wishes to stream an ordered sequence of packets to a collection of receivers, which are distributed among a number of clusters. A node may send a packet to another node in its own cluster in one time step, whereas sending a packet to a node in a different cluster takes longer than one time step. Each cluster has two special nodes. We assume that the source and the special nodes in each cluster have a higher capacity and thus can send multiple packets at each step, while all other nodes can both send and receive a packet at each step. We construct two (intra-cluster) data communication schemes, one based on multi-trees (using a collection of interior-disjoint trees) and the other based on hypercubes. We use these approaches to explore the resulting playback delay, buffer space, and communication requirements.