STUDY OF CONGESTION CONTROL ALGORITHM IN ATM NETWORKS USING SMITH'S PRINCIPLE

Abstract

Congestion control is an important issue in the network area. There are two type of congestion control policies: Open-Loop Congestion Control and Close-Close loop congestion control. Close-loop congestion control is a feedback type control. In the present work a close-loop Congestion control algorithm is described. This algorithm is for high-speed data networks like ATM networks. This algorithm is meant for Available Bit Rate (ABR) class of service in ATM networks. The algorithm used here is derived using classical control theory and Smith's dead-time compensator. The designed algorithm ensures the stability of the network queues that each transmission links have. The dynamics of the link queue is analyzed using Laplace's Transform method and classical control theory. This algorithm insures the link queue stability for different links with different propagation delays. The software simulation model of the network and the algorithm described is the major part of the whole work.