Adaptability Enhancement for Progressive Download Methods Based on Timer-Driven Requesting Schemes Using Multiple TCP Flows on Multiple Paths

Video hosting on the Internet is a new popular service, and progressive downloading methods, which download segmented video data while replaying them, are being employed by various sites. The playback rate of the video is limited by not only the maximum bandwidth of the access link but also the maximum throughput attainable over one TCP connection. The playback quality of progressive download methods can be improved by an existing method that establishes multiple TCP flows on each of multiple paths. Moreover, a timer-driven requesting scheme has been proposed; it is reported to be effective even when bandwidth, delay, and packet loss rate are not given in advance. However, it assumed the existence of just two paths with the same network condition. This paper enhances the adaptability of the previous proposal and details simulations that confirm it to be much more effective on heterogeneous paths than our earlier method. The proposal can be regarded as an assurance technology that can adapt to the heterogeneous network condition autonomously and keep the playback rate high.