ABR Traffic Control in Satellite ATM Networks

AbstructABR service relies on a feedback from the network, therefore i t strongly suffers from the long propagation delays characterizing satellite networks. In fact, i t has been shown that the high delay, in combination with high bandwidth, can deceive ABR sources and make them falsely believe that a break occurred somewhere in the path. Since ABR sources respond to breaks by reducing their cell rate, the resource utilization decreases drastically. The solution to this problem considered up to now has been to reduce the cell rate only when the feedback from the network is missing for a period longer than the round trip delay. However, this delay in reducing the cell rate causes many additional cell losses if a break actually occurs. In this paper we show the conditions in which the long propagation delay deceives the ABR sources and then propose a new ABR scheme that avoids the reduction in network utilization without causing additional losses.