Integrated optimization of distributed processing networks

During the next decade, in the wave of microelectronics and digital revolution, we can expect to witness fast growth in the number of communication-based distributed data processing systems. A communication-based distributed data processing system is a decentralized data processing system in which data processing facilities or computer resources are geographically distributed and communicate with each other through a data/computer communications network. Figure 1 typifies such an environment. The most common data/ computer communication network architectures used in the distributed environment are those illustrated in Figures 2, 3 and 4. These are the tree-shaped hierarchical, the packet and the ring-shaped architectures, respectively. These architectures are not new and heuristic algorithms have been widely available for their optimization. However, the emphasis on the distributed data processing systems shifts the application environment and objectives of the optimization problem and hence lessens the applicability of these earlier algorithms. This paper presents a set of integrated algorithms more appropriate for network optimization in this new environment. Some of the algorithms are newly developed; some are modifications of the earlier ones. Figure 2 depicts the tree-shaped, hierarchical architecture, in which the local access network defined as the circuits interconnecting the terminals and! or terminal control units, are connected to, and controlled by, the concentrating devices. The concentrating devices are in tum connected to, and controlled by, the host computer. The concentrating functions may be performed as part of a remote processor's responsibility. The circuits shown interconnecting the concentrating devices and the host computers are called the backbone network. Both the local access and the backbone networks may be point-to-point or tree-shaped connections. Occasionally, ring-shaped terminal connections may also occur. The mesh-shaped packet switching architecture is illus-· trated in Figure 3. In this architecture the local access network. comprises both the terminal devices and the hosi