LiveShift: Mesh-pull live and time-shifted P2P video streaming

Abstract

The popularity of video sharing over the Internet has increased significantly. High traffic generated by such applications at the source can be better distributed using a peer-to-peer (P2P) overlay. Unlike most P2P systems, LiveShift combines both live and on-demand video streaming -while video is transmitted through the peer-to-peer network in a live fashion, all peers participate in distributed storage. This adds the ability to replay time-shifted streams from other peers in a distributed and scalable manner. This paper describes an adaptive fully-distributed mesh-pull protocol that supports the envisioned use case and a set of policies that enable efficient usage of resources, discussing interesting trade-offs encountered. User-focused evaluation results, including both channel switching and time shifting behavior, show that the proposed system provides good quality of experience for most users, in terms of infrequent stalling, low playback lag, and a small proportion of skipped blocks in all the scenarios studied, even in presence of churn.

Playback Policies for Live and On-Demand P2P Video Streaming

“…This paper only displays results for scenarios s1 and s4, for brevity and because scenarios s2 and s3 produced expected results between s1 and s4. Multiple instances of LiveShift were executed using the same settings as in [6]. In short, peers were created with an inter-arrival time of 1 s. Every peer was programmed to repeatedly switch to a channel and starting time t 0 , then hold to the channel, attempting to locate and download blocks.…”

“…2, and share of skipped blocks n sk (t)/(n pl (t) + n sk (t)). Channel popularity and holding time were both characterized by traces, as described in [6]. Results were obtained through 10 runs of 20 minutes each.…”

“…LiveShift [6] adopts a unified policy for live and on-demand streaming which consists on skipping n contiguous missing blocks if and only if the peer holds at least 2n contiguous blocks immediately after those, otherwise stalling. It aims not to let peers stall for long in case only a few blocks are not available from current neighbors, while skipping if there is a good chance of continuing playback without interruptions.…”

“…Since users of a P2P system already collaborate on distributing video streams, LiveShift [6] makes further collaboration possible by allowing peers to store received video streams and distribute them in the future, thus enabling time shifting or -if the combined storage is large -even video-on-demand (VoD). This gives users the freedom to, without having previously prepared any local recording, watch any program from an arbitrary position in the time scale, skipping uninteresting parts until seamlessly catching up with the live stream as desired.…”

Slowing down to speed up: Protecting users against massive attacks in content distribution systems

“…Peer-to-peer (P2P) architectures have emerged as an alternative to speed up content dissemination in CDS (COHEN, 2003;ZHANG;PETER YUM, 2005;LIAO et al, 2006;HECHT et al, 2011). These architectures help balancing out the server bandwidth load.…”