Trickle: Resilient real-time video multicasting for dynamic peers with limited or asymmetric network connectivity

some of the most challenging scenarios for peer-to-peer multimedia applications arise when the applications require real-time interactions among their users. In those cases, the expectation of sub-second responses prohibits the use of popular P2P IPTV software because those programs invariably use large video buffers to amortize the propagation delays of individual frames and thus cause notable and dispersed viewing latencies among their users. The performance of these programs degrade even further if the users are connected to home networks that offer narrow uplink channels or through wireless links that experience frequent throughput fluctuations. In order to overcome these shortcomings, we develop Trickle, a peer-to-peer real-time media streaming system that can transport H.264 video streams with low link stresses (less than 250Kb/s) and stable sub-second frame delays through the use of erasure correction codes along with the clever construction of multiple multicast trees and the recruitment of many peer helpers. This paper presents the first fruits of our work including the principles and mechanisms of Trickle, its simulated performance based on H.264 video traces and its merit comparisons against Split Stream, the first application layer multicasting protocol for video streaming, and CoolStreaming, a news-making P2P IPTV program that works like BitTorrent.