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A framework for quality of service support of on-demand multicast services in the Internet

When the same information needs to be sent to many receivers, doing so using a single multicast transmission rather than a number of unicast transmissions offers several potential benefits, namely the consumption of less network bandwidth and server processing power while achieving lower transmission latency. In this thesis we focus on the use of multicast for an 'on-demand' multicast delivery system whereby the time at which the sender transmits data to the group is influenced by the current demand, that is requests for the data made by receivers. Such an ‘on-demand’ multicast delivery system might be used for both real-time streaming(e.g. audio and video) and delivery of non­ streamed information(e.g. web objects). Our aim is to develop a framework that exploits the benefits of multicast as much as possible while satisfying the QoS requirements of each sender-receiver pair. In order to achieve these goals we present 3 complimentary components in the QoS framework of an on-demand multicast delivery system. Firstly we present 2 new methods of on-demand request scheduling, that is the server process of scheduling individual transmissions of requested resources as well as determining the delivery type of each transmission, either unicast or multicast. Secondly we present a resource reservation protocol that can be used to provide data flows with QoS conunitments with regard to packet delay, loss rate and bandwidth by ensuring the availability of sufficient resources along the end-to-end path. Thirdly we present a new scheme for packet loss recovery in a multicast environment. For each of our three component contributions we analyse the relative merits compared to existing approaches and support our claims with simulation results.