Queueing Analysis of Buffered CSMA/CD Protocols

In this paper, we propose a new queueing model appropriate for the analysis of a buffered CSMA/CD protocol. We assume that each user has a finite buffer capacity. The system, in general, can be modeled as a multidimensional semi-Markov chain. The enormous state space for the complete description is reduced by appropriate exploitation of the features of the system, e.g., fairness towards all users, dependence of the probability of successful transmission only on the total number of busy users, etc. Using a further assumption we construct a two-dimensional semi-Markov chain, examining the state of the system immediately after the successful transmission of packets. The obtained solution is extremely accurate and exhibits excellent agreement with simulation results, which corroborates the correctness of our method.