Flow control for the ATM available bit rate service

During the past year the identification of appropriate flow control mechanisms for the support of the new available bit rate (ABR) ATM service has attracted the intense interest of the technical community worldwide. A key aspect of the ABR service definition is the reliance an a feedback control loop linking the potential points of congestion in an ATM network and the sources of data. The feedback control of the flow of data cells within multiservice networks characterized by both extremely high data rates, and possibly long propagation delays poses formidable challenges. This is particularly true when very strict quality of service requirements are imposed, together with the need to reduce expensive buffering needs. In this paper the author discusses some fundamental and sometimes new control aspects brought to the surface by the intense effort towards the definition of appropriate feedback flow control schemes for the ABR service. The primary goal for the ABR service is the economical support of applications with vague requirements for throughputs and delays