ABR traffic control in satellite ATM networks

The ABR service relies on feedback from the network, therefore it strongly suffers from the long propagation delays characterizing satellite networks. In fact, it has been shown that the high delay, in combination with the 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. 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.