A Hierarchical Group Communication Protocol for Scalable Total Ordering

In parallel and distributed systems, a great deal of members in a group are cooperating to achieve some functions. But in a traditional group communication system, there are lots of communication overheads, especially when membership of group changes frequently. These overheads will greatly degrade the efficiency of group communication system. In this paper, a novel hierarchical group communication protocol called RHGP is proposed. RHGP is the acronym of “ring-based hierarchical of group protocol”. This protocol supports total order message delivery and hierarchical group management by using token passing. It also supports dynamical changing of the membership of a group. In order to reduce communication overheads and improve reliability, the protocol decreases the number of messages exchanged during the membership changing of a group. It is proved that the proposed protocol is reliable in the sense that with high probability of 99.8646% a ring-based hierarchy with nearly 200 members can work well when member faulty probability is bounded by 0.1%; if at most 3 members faulty are allowed, reliability probability of hierarchy is 99.9999%. It is also proved that the proposed protocol is scalable in the sense that with the number of group members increasing, reliability probability of hierarchy decreases slowly.