A Proposal for A Scalable Internet Multicast Architecture

We propose a new network and system architecture for multicast in the Internet. Our main objectives are to find a cost-effective way to scale to a large number of multicast groups whose members are geographically dispersed; and to enable small and less capable devices to participate in group communications. In order to preserve the efficiency of data distribution gained by multicast, while avoiding the control complexity previously exhibited by IP multicast, we propose the use of an overlay network for multicast services. We construct “virtual” multicast trees, which consist of unicast connections joining multicast servers in the network. These servers represent their end users who are interested in communicating together, and replicate and forward data on their behalf. A network design problem is presented to study the implication of such overlay network. On top of this network communication channel, we devise a transport layer and system architecture to provide crucial functionalities to applications. In addition, we propose a multicast mechanism that involves only end-systems. This allows accelerated application deployment without the need of network infrastructure support. To gain experience of the interfacing between applications and the multicast communication channel, we implement a multicast middleware package and prototype applications for future experiments.