Fast Atomic Multicast

Atomic multicast is a communication building block of scalable and highly available applications. With atomic multicast, messages can be ordered and reliably propagated to one or more groups of server processes. Because each message can be multicast to a different set of destinations, distributed message ordering is challenging. Some atomic multicast protocols address this challenge by ordering all messages using a fixed group of processes, regardless of the destination of the messages. To be efficient, however, an atomic multicast protocol must be genuine: only the message sender and destination groups should communicate to order a message. In this paper, we present FastCast, a genuine atomic multicast algorithm that offers unprecedented low time complexity, measured in communication delays. FastCast can order messages addressed to multiple groups in four communication delays, messages addressed to a single group take three communication delays. In addition to proposing a novel atomic multicast protocol, we extensively assess its performance experimentally.