Best-Effort Patching for Multicast True VoD Service

A multicast Video-on-Demand (VoD) system allows clients to share a server stream by batching their requests, and hence, improves channel utilization. However, it is very difficult to equip such a VoD system with full support for interactive VCR functions which are important to a growing number of Internet applications. In order to eliminate service (admission) latency, patching was proposed to enable an existing multicast session to dynamically add new clients, and requests can be served without delay if patching channels are available. A true VoD (TVoD) service should support not only zero-delay client admission but also continuous VCR-like interactivity. However, the conventional patching is only suitable for admission control. We propose a new patching scheme, called Best-Effort Patching (BEP), that offers a TVoD service in terms of both request admission and VCR interactivity. Moreover, by using a novel dynamic merging algorithm, BEP significantly improves the efficiency of TVoD interactivity, especially for popular videos. We also model and evaluate the efficiency of the dynamic merging algorithm. It is shown that BEP outperforms the conventional TVoD interaction protocols.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47328/1/11042_2005_Article_6851.pd

Providing VCR Functionality in VOD Servers

Resource-sharing techniques are widely used by VOD servers. Stream merging is one of the most efficient resource-sharing techniques. ERMT is able to achieve merge trees with the closest cost of optimal merge tree. Full VCR support has become a “must have” feature for VOD services. This researcher proposed an algorithm to enable VCR support on ERMT. Furthermore, client local buffer and fixed-interval periodical multicasting were also deployed by the algorithm to improve the stream-client ratio. After thorough runs of simulations and numerous comparisons to BEP, the highly efficient resource- sharing technique, the proposed algorithm with client local buffer utilization and fixed- interval multicasting showed better performance in all simulations. The biggest discovery is that the best-performer is modified ERMT with client local buffer support for VCR without fixed-interval multicasting. Another discovery is that bigger client buffer size hurts the performance of ERMT