An increasingly common feature of a Set Top Box (STB) is that of a Personal/Digital Video Recorder (PVR), which
enables subscribers to record broadcasted content to be viewed at a later time--time-shifting. Currently, subscribers have
the limited choice of watching time-shifted shows either from their own PVRs or from a centralized VoD server that makes
available only the popular shows for time shifted viewing. Our CommunityPVR-a new system that forms a peer-to-peer
network among the STBs and streams recorded content among peer STBs-makes available less popular titles to niche
audiences (the long tail effect) of a community without incurring addtional cost to service providers for servers, bandwidth,
and storage. In this paper, we present an analytical model to investigate how far along the tail of the popularity curve can
be covered by CommunityPVR. Using TV shows ranked by Nielsen Media Research and VoD shows from China Telecom,
our model provides a framework to determine the number of copies of broadcast/VoD content recorded by a community
and the probability that CommunityPVR is able to deliver an on-demand stream of a given show over a DSL network. For
example, CommunityPVR can stream near DVD quality video of the top ranked 5000 shows with 100% probability to a
community of 100K. Unlike a centralized VoD solution, CommunityPVR has the potential to deliver both popular and long
tail content on demand to a service provider's community in a cost-effective manner.
Multihoming provides highly diverse redundant paths in terms of average hop count, latency, loss ratio, and jitter. In this paper, we first explore topological path diversity and show that multihoming can significantly reduce the path overlap when a multihomed receiver conducts media streaming from a set of suppliers. We then design a multihome-aware media streaming system (MMS) that exploits topological path diversity by splitting a streaming session over the available physical links to reduce path overlap among the suppliers, and migrating a connection from one path to another if the current path is congested. A network tomography-based monitoring mechanism is developed to identify congested path segments. Through a series of experiments in the wide area Internet, we show that multihoming provides streaming at a higher rate comparing to a single service provider. On average the quality of streaming sessions is improved by 30% or more.
We study data integrity verification in peer-to-peer media streaming for content distribution. Challenges include the timing constraint of streaming as well as the untrustworthiness of peers. We show the inadequacy of existing data integrity verification protocols, and propose Block-Oriented Probabilistic verification (BOPV), an efficient protocol utilizing message digest and probabilistic verification. We then propose Tree-based Forward Digest Protocol (TFDP) to further reduce the communication overhead. A comprehensive
comparison is presented by comparing the performance of existing protocols and our protocols, with respect to overhead, security assurance level, and packet loss tolerance. Finally, experimental results are presented to evaluate the performance of our protocols.
Conference Committee Involvement (2)
Multimedia Computing and Networking 2008
30 January 2008 | San Jose, California, United States