Implementation of dynamic service aggregation for interactive video delivery
Prithwish Basu, Ashok Narayanan, Rajesh Krishnan, Thomas D. C. Little · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1997
Conventional video-on-demand (VoD) servers providing VCR-like interactivity allocate a separate channel for each user. Various schemes have been proposed for aggregating users into groups to improve resource utilization. By bridging the temporal skew between users viewing the same content, multiple users can be served from a single channel. Dynamic aggregation techniques such as rate adaptation and content insertion attempt to optimize resource utilization on-the-fly, thus improving their performance in interactive situations. In this paper, we describe a VoD system which delivers continuous media content to multiple clients using dynamic service aggregation to reduce bandwidth requirements. MPEG-1 system streams are used as the content format and IP multicast is used for video delivery. To the best of our knowledge, we are the first to demonstrate the viability of dynamic service aggregation using rate-adaptive merging in a VoD system. We present our experiences with building the system and address some important issues relating to aggregation in video servers including server directed channel switching in the client and stream merging by acceleration. We show simulations of our clustering and merging algorithms for large user populations and report the piggybacking of over 2.5 users on average per physical channel.