Performance analysis of FDDI LANs using numerical methods

Abstract

Simulators are valuable tools; they help in understanding how complex systems will operate and perform without actually having to build a physical model to test. However, they often require extensive development and run times. This is especially true for many networks such as FDDI, where a large number of nodes and priority classes are involved. A high-level algorithm is presented to evaluate the performance characteristics of a token LAN. The goal of the research was to find a method for obtaining an estimate of the average access delay, and the average end-to-end delay of advanced token-ring networks. The FDDI (fibre distributed data interface) standards were used as the basis of a FFOL (FDDI follow-on LAN) solution. A method was developed that will generate exact results for such networks at low- to medium-load network environments. As the load level increases, the error rate of the estimate also increases; this however is monitored and can be used as a confidence measure for the results obtained. A symmetric multimedia environment is used in the model, with bimodal traffic consisting of short data packets, and longer video packets. A short introduction to the network setup and the examination of the method developed is presented in single and multinetwork environments. Specific network parameters were chosen for these experiments, but the method is easy to customise to other network parameters.