Research Studies Project Report (M.Eng.) - Asian Institute of Technology, 1994

A research submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Engineering and Technology

Connection Admission Control (CAC) scheme is an important part of the congestion control mechanism being identified in an ATM environment. It is a preventive control mechanism. Several CAC schemes using an upper bound for Cell Los~ Probability (CLP) have been proposed. Saito's Upper bound method and the Three Parameter Scheme, proposed by Chamila work on obtaining an upper bound for the CLP. While Saito's scheme is definitely an upper bound, the use of the buffer size parameter in obtaining this upper bound can be eliminated as shown in this study, thus reducing it to a buffer less fluid flow model. Three Parameter Scheme on the other hand looses in the gain achievable due to its somewhat arbitrary selection criteria for the selecting the observation interval. A new selection criteria fonnulated in this study provides a better link utilization. Traffic shaping mechanisms have been considered as prut of the UPC/NPC functions which determine the confo1mance of a source traffic to the negotiated traffic parameters, during c.ell set up phase. Two types of traffic shaping methods , burst splitting and cell dispersion in time, a.re studied. It is established that the cell dispersion in time provides better Cell Loss Probability characteristics for the same amount of delay variation introduced compared to the burst splitting method.