Analysis of a New Retransmission Control Algorithm for Slotted CSMA/CD LAN´s

Algorithms for the control of the retransmission procedure in random multiple access schemes are needed to ensure stability of the system operation under high traffic conditions. Optimal retransmission control policies cannot be applied in practice since they are based on global information about the system state. In the case of the most well-known implementation of the CSMA/CD protocol, ANSI/IEEE Std 802.3-1985, a heuristic approach, known as the "truncated binary exponential backoff" algorithm, is employed. Such schemes are not amenable to theoretical analysis because of the state space. explosion problem of the underlying Markovian model. In this paper, a new retransmission control algorithm, suitable for CSMA/CD protocols, based on information acquired by monitoring the channel transmissions is proposed. A Markovian model is presented and the algorithm is analyzed in detail. The performance of the algorithm is evaluated, several numerical and simulation results are presented and comparisons to other protocols are made.