Model of Optimal Placing Information Resources is Solved on Distributed Information System Enterprise on the Basis of Two-Lewel «Client – Server» Architecture with Cosidering the Influence Of Blocings

Abstract

The unique conceptual model of enterprise distributed information system is obtained in this paper. This model does not represented in the Queuing theory and is based on the client-server local area network architecture with the restrictions by the synchronization type «department-department», «arrival-arrival» of one-time parallel requests. However, due to the complexity of this system`s analytical description some simplifications are introduced. The «department-department» problem is solved by the assumptions that process of dividing the parallel request to the simple transactions goes not at the same time, but sequentially one by one. The «arrival-arrival» problem is solved by entering the data buffers for the terminals, which assemble answer messages and the keys used for passing the assembled answer of the whole request. The mathematical model of network state`s steady-state probabilities definition is designed for this conceptual model using an apparatus of closed exponential queuing networks, base correlations for the transition matrix construction are given. Modified correlation for the service intensities calculation at the network nodes are given for the distributed information system mode taking the account of lock influence. Using a previously developed algorithm, the problem of optimal allocation of information resources is solved on computer network nodes on the criterion of minimum average response time of the system to user requests. The results of numerical experiments are given in this paper.