Research On Transmission And Schedule Algorithms Of Multi-source Peer-to-Peer Media Streaming

Based on quantity of sending peers, P2P media streaming can be classified into two categories: single source peer-to-peer media streaming and multi-source peer-to-peer media streaming. In fact, a single serving peer may not be able or willing to contribute an upload bandwidth enough for the media playback at the receiver. This multipoint-to-point communication can provide a higher overall throughput to the receiver, hence resulting in a higher quality. PROMISE system is a typical representative of multi-source peer-to-peer media streaming.Transmission and schedule strategies on multi-source peer-to-peer media streaming mainly include the following two aspects: (1) selecting active sending peers from the candidate set; (2) scheduling data packets to receiver by all active sending peers cooperatively. To aim at research of stability improvement and latency shortening in PROMISE system, more perfect transmission and schedule algorithms of multi-source peer-to-peer media streaming are designed, named IPROMISE. For the aspect of active sending peers selection, based on technology of topology-aware selection in PROMISE, IPROMISE gives the algorithm of active sending peers selection by adaptive rate adjustment mechanism based on occupied state of receiver peer's buffer, degree of receiver peer's score and level of network congestion. The algorithm sufficiently pays attention to adjustment role of buffer and adaptive capability to network environment, and adopt stimulation mechanism to urge peers to contribute their resources. As for the aspect of data packets assignment, policy adopted in IPROMISE is to try to make data packets arrive according to packet sequence number at the stage of start playback, to make sure start latency minimized.IPROMISE can adjust aggregated bandwidth to adapt itself environment variation, so that it can provide stability of playback quality even though network environment isn't stable. Simulations show, on the assumption that network topology is built, compared with PROMISE, IPROMISE can greatly shorten start delay, and better guarantee stability of playback quality.