CAM02-4: Online Management of QoS Enabled Overlay Multicast Services

More and more, content providers offer multimedia services such as Internet TV, multimedia conferencing and online gaming to their customers. These services are characterized by their high sensitivity to network delay and a multicast nature. An overlay network allows for supporting QoS by making reservations in the underlying networks and for multicasting the multimedia streams towards their targets at the overlay layer, without requiring multicast support from the underlying networks. This paper outlines the architecture of a dynamic QoS enabled multicast overlay network and also introduces a set of algorithms to determine an overlay distribution tree that connects a multimedia server to a number of clients. The algorithms construct a tree with a bounded end-to-end delay and minimize the bandwidth that is used. These algorithms are evaluated in terms of bandwidth cost, overlay cost and end-to-end delay. We show that one of our heuristics finds overlay multicast trees that approximate the optimal result in terms of cost and that have a small diameter and a low average delay.