Analysis of Block-aware Peer Adaptations in Substream-based P2P

Peer-to-Peer (P2P) video delivery using substreams supports uplink heterogeneities of the peers and hence could optimise sharing capabilities with minimum free-riding peers. Therefore, substream-based applications such as PPLive and CoolStreaming have been well accepted after successful deployments in the public Internet. In this approach, a child peer can find a parent peer for a substream independent of the other parent peers that it receives the remaining substreams. In general, there can be more than one substream between a parent and a child. The block-aware adaptation algorithm in CoolStreaming changes the parent peer for all such substreams when a child peer experiences poor performance even on one of its substreams from the parent. However, lagging of one substream in such a scenario is likely while others are not affected, when the parent receives its substreams through multiple paths. We propose a fine-grained approach (changing substream by substream) in peer adaptations to improve overlay network performance. This approach will in turn, is designed also to minimise the diversity of parents at the child peer by joining with a well-performing another parent, which is expected to curtail complexities in a network-assisted P2P framework

Understanding Sub-stream Scheduling in P2P Hybrid Live Streaming Systems

The P2P pull-push hybrid architecture has achieved great success in delivering live video traffic over the Internet. However, a formal study on the sub-stream scheduling problem, a key design issue in hybrid systems, is still lacking. In this paper, we propose a max-flow model for mathematical analysis of this problem. We find that the sub-stream scheduling schemes used in existing hybrid systems, including CoolStreaming+, GridMedia and LStreaming, individually solve one special case of the proposed max-flow model. Moreover, this model can also serve as a benchmark to assess the performance of these existing sub-stream scheduling schemes. Further, we propose a weighted max-flow scheme to address the issue of peer heterogeneity in scheduling sub-streams. Finally, we point out the benefits of combining the hybrid streaming architecture and layered coding, and we also investigate how to schedule sub-streams in hybrid layered streaming systems