Efficient network QoS provisioning based on per node traffic shaping

This paper addresses the problem of providing per-connection end-to-end delay guarantees in a high-speed network. We assume that the network is connection oriented and enforces some admission control which ensures that the source traffic conforms to specified traffic characteristics. We concentrate on the class of Rate-Controlled Service (RCS) disciplines, in which traffic from each connection is reshaped at every hop, and develop end-to-end delay bounds for the general case where different reshapers are used at each hop. In addition, we establish that these bounds can also be achieved when the shapers at each hop have the same 'minimal' envelope. The main disadvantage of this class of service disciplines is that the end-to-end delay guarantees are obtained as the sum of the worst case delays at each node, but we show that this problem can be alleviated through 'proper' reshaping of the traffic. We illustrate the impact of this reshaping by demonstrating its use in designing RCS disciplines that outperform GPS-based service disciplines.