Performance Analysis of FDDI LANs using Numerical Methods

摘要

Simulators are valuable tools in helping us understand how complex systems will operate and perform, without actually having to build a physical model to test. It is best to write the simulator in a higher level programming language, in our case we use Mathematica and are able to obtain fast results with excellent graphing capabilities. The goal of our research is to find a method for obtaining an estimate of the average access delay for advanced token ring based networks such as FDDI (fiber distributed data interface) or FFOL (FDDI follow on LAN). We have developed a method that will generate exact results at low to medium loaded networks. As the load level increases, the error rate also increases, this however is monitored and can be used as a confidence measure for the results obtained. A symmetric multimedia environment is used as the model, with bi-modal traffic consisting of short data packets and longer video packets. The method we developed to calculate the estimated average access time under a specific network configuration as a function of varied offered load. A full listing of the Mathematica code is included in the Appendix and is referenced in the analysis section.