Group communication protocol in transaction-oriented applications

In group communications, larger computation and communication are consumed to causally order all the messages transmitted in the network. Transactions in clients manipulate objects in servers by sending read and write requests to the servers. In this paper we define significant messages by using the relation among the transactions. We newly propose an object vector to causally order only the significant messages. The scheme of the object vector is invariant in the change of the group membership. We also show a TBCO (transaction-based causally ordered) protocol which adopts the object vector by which the number of messages to be causally ordered are reduced.