Reaching Real Agreement in an Unknown Network Environment

Abstract

The Byzantine Agreement problem is one of the most fundamental problems in the field of distributed environment. It requires a set of the processors to agree on a common value even if some processors are corrupted. There are many significant studies about these problems in a well-defined network environment. These network like the FCN (Fully Connected Network), GCN (Generalized Connected Network), and SGCN (Super Generalized Connected Network) discussed about vary faults of processors and transmission media. Thus, we can understand the faulty tolerant capability of these network environments. But it is computationally infeasible for ignoring the network structure in a real environment. In general, the processors will turnover the network arbitrary in any time. Thus, the network will become an instable state that influences the system to reach a common value. Subsequently, the fault tolerant capability will unable to be computed due to each processor doesn’t know any connectivity of other processors. Thus, this paper will discuss about this serious problem that vary network environment. This kind of the network, we call it as an Unknown Network (UNet) structure. And this paper proposes the solution for Byzantine Agreement in a UNet environment. These assumptions will generate some different results with prior literatures. Similarly, our proposed protocol can solve the Byzantine Agreement using minimum rounds of message exchange, and tolerates the maximum number of transmission media failure.