Obtaining consistent good/bad plan set in the presence of faults

In a cooperative network, we need a mechanism that allows all correct processors to reach a common agreement. Hence, more and more attention has been drawn on the agreement related problems (Byzantine Agreement (BA) problem and Consensus problem). In previous results, the goal of BA and Consensus is obtaining a common value no matter this value is good or bad. To address this problem, Correia, Bessani and Veríssimo proposed the Byzantine Generals with Alternative Plans (BGAP) protocol that requires the common value come from the good plan set. BGAP is a graceful and practical protocol. They also pointed out that the BA problem with alternative plans is unsolvable if correct processors have different good plans and bad plans. In this paper, we propose the Plan_Consensus Protocol (PCP) to ensure that all correct processors obtain a consistent good plan set and a consistent bad plan set in the network.