P2P Live Streaming Systems Research Articles

A modeling framework of content pollution in Peer-to-Peer video streaming systems

Peer-to-Peer (P2P) live video streaming systems are known to suffer from intermediate attacks due to its inherent vulnerabilities. The content pollution is one of the common attacks that have received little attention in P2P live streaming systems. In this paper, we propose a modeling framework of content pollution in P2P live streaming systems. This model considers both unstructured and structured overlays, and captures the key factors including churns, user interactions, multiple attackers and defensive techniques. The models are verified with simulations and implemented in a real working system, Anysee. We analyze content pollution and its effect in live streaming system. We show that: (1) the impact from content pollution can exponentially increase, similar to the random scanning worms, leading to playback interruption and unnecessary bandwidth consumption; (2) content pollution is influenced by peer cooperation, peer degree and bandwidth in unstructured overlays, and topology breadth in structured ones; (3) the structured overlay is more resilient to content pollution; (4) a hybrid overlay result in better reliability and pollution resistance; (5) hash-based chunk signature scheme is most promising against content pollution.

A fine-grained balancing scheme for improved scalability in P2P streaming

In this paper, we relax the restriction imposed in our previously proposed balancing scheme that a peer is allowed to forward only one specific description to others, and propose the fine-grained balancing scheme to further improve the scalability of P2P live streaming systems based on multiple description coding (MDC) techniques. Like the balancing scheme, the fine-grained balancing scheme is capable of balancing the distribution of descriptions and streaming workload among peers by means of a centralized description allocation scheme. Moreover, relaxing the restriction on peers' description provision enables the proposed fine-grained balancing scheme to utilize peers' outbound bandwidth more flexibly and efficiently than the balancing scheme. The experiment results show that with the proposed scheme the utilization of peers' bandwidth can be greatly improved, thereby reducing the server bandwidth consumption and the rejection rate. As a result, more peers can be served and peers are enabled to recover from failure mostly by themselves with little server involvement.

Efficient User Authentication and Key Management for Peer-to-Peer Live Streaming Systems

Recent development of the peer-to-peer (P2P) live streaming technique has brought unprecedented new momentum to the Internet with the characters of effective, scalable, and low cost. However, before these applications can be successfully deployed as commercial applications, efficient access control mechanisms are needed. This work based on earlier research of the secure streaming architecture in Trust-Stream, analyzes how to ensure that only authorized users can access the original media in the P2P live streaming system by adopting a user authentication and key management scheme. The major features of this system include (1) the management server issues each authorized user a unique public key certificate, (2) the one-way hash chain extends the certificate's lifetime, (3) the original media is encrypted by the session key and delivered to the communication group, and (4) the session key is periodically updated and distributed with the media. Finally, analyses and test results show that scheme provides a secure, scalable, reliable, and efficient access control solution for P2P live streaming systems.

On the impact of playout scheduling on the performance of peer-to-peer live streaming

In this paper we examine the impact of the adopted playout policy on the performance of P2P live streaming systems. We argue and demonstrate experimentally that (popular) playout policies which permit the divergence of the playout points of different nodes can deteriorate drastically the performance of P2P live streaming. Consequently, we argue in favor of keeping different playout points ''near-in-time'', even if this requires sacrificing (dropping) some late frames that could otherwise be rendered (assuming no strict bidirectional interactivity requirements are in place). Such nearly synchronized playout policies create ''positive correlation'' with respect to the available frames at different playout buffers. Therefore, they increase the number of upstream relay nodes from which a node can pull frames and thus boost the playout quality of both single-parent (tree) and multiple-parent (mesh) systems. On the contrary, diverging playout points reduce the number of upstream parents that can offer a gapless relay of the stream. This is clearly undesirable and should be avoided as it contradicts the fundamental philosophy of P2P systems which is to supplement an original service point with as many additional ones presented by the very own users of the service.

Inferring Network-Wide Quality in P2P Live Streaming Systems

This paper explores how to remotely monitor network-wide quality in mesh-pull P2P live streaming systems. Peers in such systems advertise to each other buffer maps which summarize the chunks of the video stream that they currently have cached and make available for sharing. We demonstrate how buffer maps can be exploited to monitor network-wide quality. We show that the information provided in a peer's advertised buffer map correlates with that peer's viewing-continuity and startup latency. Given this correlation, we remotely harvest buffer maps from many peers and then process these buffer maps to estimate the video playback quality. We apply this methodology to a popular P2P live streaming system, namely, PPLive. To harvest buffer maps, we build a buffer-map crawler and also deploy passive sniffing nodes. We process the harvested buffer maps and present results for network-wide playback continuity, startup latency, playback lags among peers, and chunk propagation patterns. The results show that this methodology can provide reasonably accurate estimates of ongoing video playback quality throughout the network.