On Achieving Pro t in Providing Near Video - on - Demand ServicesS

1 On Achieving Pro t in Providing Near Video-on-Demand Services S.-H. Gary Chan Fouad A. Tobagi Department of Electrical Engineering Stanford University Stanford, CA 94305 Abstract| In near video-on-demand, requests for the same movie arriving within a period of time are grouped together (i.e., batched) and served with a single multicast stream; thereby reducing the bandwidth requirement compared with the unbatched case. We consider here that the use of a multicast channel comes with a cost. Since delayed users may cancel their requests while being batched, this uncollected revenue has to be appropriately balanced with the channel usage cost in order to achieve maximum pro t. We address here pro t issues for a number of batching schemes. In the window-based schemes, users are batched for a xed period of time before they are served; in the batch-size based scheme, users are served once a certain number of them are collected. We study the system pro t in terms of user reneging behavior, movie popularity, and multicast channel cost. By combining the advantages of the window-based and the batchsize based schemes, we introduce a scheme which adapts to the uctuating request rate to achieve high pro t. Keywords|Near video-on-demand, request batching and multicasting, network channel cost, user reneging behavior, pro t issues