Modeling and performance evaluation of distributed systems as part of the development of ruggedized control and command systems

Recently developed ruggedized command control information systems (CCIS) are distributed systems which usually include heterogeneous hardware and software. The authors introduce modelling techniques used for performance evaluation of CCIS. CCIS are composed of processing centers linked together through wide-area networks. These centers are distributed systems of computers connected through local area networks. Processing centers include databases as well as application software packages running concurrently on different computers. A model has been built using a queuing network formalism to forecast the different computers and link loads under various hypotheses. An appropriate dimensioning of the system and load balancing have been determined to help avoid bottlenecks at an early design stage. Moreover, the evaluation of response times on very complex applications and message processing has been used to validate the system´s architecture