EFFICIENCY EVALUATION OF ENTERPRISE INFORMATION SYSTEMS WITH NON-UNIFORM LOAD

The paper deals with the problem of characteristics evaluation for enterprise information systems at the design stage. In the design of ERP-systems the most interest characteristic is not the average time, but the probability of timely delivery of different type messages (for example, command, service, multimedia, files, etc.) from the sender to the recipient. In addition,the possibility of using the priority information management built on the basis of service disciplines of general form with mixed priorities needs to be considered. An open queuing network with non-uniform data flow is used for solution of this problem. The method for calculation of information systems characteristics is proposed based on the decomposition of the network model. The end results obtained with this approach and by means of priority management are approximate because different classes of message streams at the output and input nodes of the computer system differ from the simple ones. However, result errors of the proposed analytical method are in acceptable limits for engineering calculations as it was shown by simulation in a wide range of parameters corresponding to real systems. Obtained results are usable for optimization problem solution of data transmission networks in modern information systems, involving routing algorithm definition and priorities specification for different classes of messages to provide given delivery time.