Causally Ordering Broadcast Protocol

The distributed applications require group communications among multiple entities. In the group communication, it is important to discuss in what order each entity in the group can receive data units. In order to realize fault-tolerant systems, the same events have to occur in the same order in each entity. The ordering among the events is known as a causal order. This paper presents a reliable causally ordering broadcast (CO) protocol which provides the same causal ordering of data units for all the entities in the group. In the CO protocol, the data units received are causally ordered by using the sequence numbers of the data units. The CO protocol is based on the fully distributed control scheme, i.e. no master controller, and uses high-speed networks where each entity may fail to receive data units due to the bu er overrun. Furthermore, the CO protocol provides asynchronous data transmission for multiple entities in the group.