Gossip-based broadcast algorithms have been considered as a viable alternative to traditional deterministic reliable broadcast algorithms in large scale environments. However, these algorithms focus on broadcasting events inside a large group of processes, while the multicasting of events to a subset of processes in a group only, potentially varying for every event, has not been considered We propose a scalable gossip-based multicast algorithm which ensures, with a high probability, that (1) a process interested in a multicast event delivers that event (just like in typical gossip-based broadcast algorithms), and that (2) a process not interested in that event does not receive it (unlike in broadcast algorithms).
