Exact and Approximate Models to Obtain Average Throughput of the FDDI MAC Protocol - Part I: Symmetric Systems

• Main Authors: LIM, K. S., DENG, Robert H., Ranai, K.
• Format: text
• Language: English
• Published: Institutional Knowledge at Singapore Management University 1994
• Subjects: Information Security
• Online Access: https://ink.library.smu.edu.sg/sis_research/199; http://dx.doi.org/10.1016/S0140-3664(05)80013-1
• Institution: Singapore Management University

Although the FDDI MAC protocol has been studied quite extensively, many of the analyses that have been performed so far are complex approximations and require a significant number of simplifying assumptions to be made to the protocol to keep their solution tractable. The need for these simplifications and the general difficulty (often requiring the use of numerical methods) in obtaining these approximate solutions, limit the scope and usefulness of the results to only simple cases. In the first part of this two-part paper, we present an alternative method for computing the exact mean throughput of a symmetric FDDI network with both asynchronous and synchronous transmissions using a simple mean value approach. Closed form solutions for the exact mean throughput and token rotation time of a single priority symmetric network are derived. For networks with multiple levels of priorities, an iterative algorithm is presented which allows the same quantities to be computed. The approach works even when the synchronous traffic stream is not saturated. Results of extensive computer simulations used to verify the accuracy of our approach are also presented. Part two of the paper will propose an alternative approach for computing the approximate mean throughput of a multiple priority asymmetric FDDI network with both synchronous and asynchronous transmission.