Brief announcement: global consistency can be easier than point-to-point communication

Global consistency or Byzantine Agreement (BA) and reliable point-to-point communication are two of the most important and well-studied problems in distributed computing. Informally, BA is about maintaining a consistent view of the world among all the non-faulty players in the presence of faults. In a synchronous network over n nodes of which up to any t are corrupted by a Byzantine adversary, BA is possible only if all pair point-to-point reliable communication is possible [Dol82, DDWY93]. Specifically, in the standard unauthenticated model, (2t + 1)-connectivity is necessary whereas in the authenticated setting (t + 1)connectivity is required. Thus, a folklore is that maintaining global consistency is at least as hard as the problem of all pair point-to-point communication. Equivalently, it is widely believed that protocols for BA over incomplete graphs exist only if it is possible to simulate an overlay-ed complete graph. Surprisingly, we show that the folklore is far from true -- ...

• Type: Conference
• Year: 2009
• Where: PODC
• Authors: Prasant Gopal, Anuj Gupta, Pranav K. Vasishta, Piyush Bansal, Kannan Srinathan
• Keywords: Pair Point-to-point Communication, Parallel Computing, PODC 2009, Point-to-point Communication, Reliable Point-to-point Communication