Based on a logical token ring, this communication protocol ensures total message ordering and atomic delivery, so all group members maintain an identical view of ordered events. RMP (Reliable Multicast Protocol) is an efficient multicast protocol for general distributed applications based on the logical token ring approach. The novelty of RMP is that it simultaneously multicasts an ordered message and implicitly rotates the token position on the ring. There is no token transfer message in the normal multicast. For message atomicity, our protocol minimizes control messages and communication costs while incurring a relatively short delay. In contrast to other token algorithms, RMP does not risk losing the token when the token site fails. Without requiring extra overhead, our approach guarantees total ordering of messages and message atomicity-either every member receives a message, or none do.