A multicast protocol based on a single logical ring using a virtual token and logical clocks

A novel and highly efficient multicast protocol based on single logical ring for a group of cooperative processes is presented. It maintains consistency in the group by two strategies. First, by placing a total sequence number in each multicast message, the protocol guarantees total ordering of the messages. Second, in contrast to other token-passing ring protocols, it uses a virtual token to achieve atomicity of messages. That is, no real token is rotating on the ring and the position of the holder of the virtual token is calculated by using a logical clock in each process without using messages for passing the token. It achieves message atomicity by using up to n point-to-point control messages. The protocol can tolerate communication faults, process crash failures and network partitioning. Correctness of the protocol is proved