Virtual Grouping Byzantine Agreement: A compromised consensus scheme for a cooperative network

In a cooperative network environment, each independent node communicates with others by some agreement mechanism to make sure the majority of nodes can actuate a common corresponding action. Byzantine Agreement (BA) has been proved to effectively make all healthy nodes obey the same command issued from the commander node. The major challenge for BA is its considerable amount of exchange messages among nodes to reach the consensus, especially when BA is applied to a network environment which comprises lots of cooperative nodes. Based on above, we propose a Virtual Grouping Byzantine Agreement (VGBA) scheme to compromise between the percentage of nodes which can obtain the common command and the number of exchange messages. VGBA may suffer a lowered tolerance capability of faulty nodes and a lowered percentage of healthy nodes having the command but significantly reduce the message volume so that the improved scheme is applicable while facing a larger number of nodes. The theoretical inferences and evaluation results show that the proposed scheme provides an effective trade-off solution to the agreement problem among cooperative distributed nodes in terms of message volume and fault tolerance in an autonomous network.