Object-based message ordering in group communication

In distributed applications, a group of multiple objects cooperate. Group communication protocols have been discussed, which support the reliable and ordered delivery of messages at the network level. However, only messages to be ordered at the application level are required to be causally delivered. The state of the object depends on the order in which the conflicting requests are computed and the responses and requests are transmitted. The authors define the object-based precedence order of messages based on the conflicting relation among the requests. They discuss a protocol which supports the object-based ordered delivery of request and response messages.