Multicast is an efficient communication technique to save bandwidth for group communication purposes. A number of protocols have been proposed in the past to provide a reliable multicast service. Briefly classified, they can be distinguished into sender-initiated, receiver-initiated and tree-based approaches.

In this paper, an analytical bandwidth evaluation of generic reliable multicast protocols is presented. Of particular importance are new classes with aggregated acknowledgments. In contrast to other approaches, these classes provide reliability not only in case of message loss but also in case of node failures. Our analysis is based on a realistic system model, including data packet and control packet loss, asynchronous local clocks and imperfect scope-limited local groups.

Our results show that hierarchical approaches are superior. They provide higher throughput as well as lower bandwidth consumption. Relating to protocols with aggregated acknowledgments, the analysis shows only little additional bandwidth overhead and therefore high throughput rates.