ABSTRACT
Distributed systems based on decentralized control are becoming increasingly important; a good example is the Internet. A well-designed decentralized control system offers the potential of high performance, reliability, and scalability, to a much greater degree than distributed systems with centralized control. However, there are certain significant problems that arise in these systems that inhibit coordination. These problems are fundamental: They are an inherent part of any system where there are multiple decision makers and communication between them takes significant time. These problems can never be eliminated completely; they can only be dealt with by minimizing the damage that results from them, or by lowering the probability that their negative effects will occur. Indeed, it is a tribute to the power of distributed systems that, despite these problems, it is still worth building systems based on decentralized control.
