Atomic Multicast harder than Atomic Broadcast
Rachid Guerraoui, A. Schiper · 1996
Atomic broadcast and atomic multicast are communication primitives which ensure that processes agree on the sequence of messages they deliver. Whereas atomic broadcast is used to send messages to the set of all the processes in the system, atomic multicast sends messages to specific subsets of processes. We say that an atomic multicast algorithm is "genuine", if only the sender and the destination processes of a message take part in the protocol needed to deliver the message. We formally define the genuine atomic multicast problem, and we show that this problem turns out to be harder than the atomic broadcast problem. Whereas atomic broadcast can be solved with unreliable failure detectors that can make false failure suspicions, we show that atomic multicast cannot. Keywords. Atomic multicast, atomic broadcast, asynchronous system, crash failure, reliable channel, failure detector. 1 Introduction The motivation of this work was to find out whether the results stated by Chandra and T...