On the impacts of traffic shaping on end-to-end delay bounds in aggregate scheduling networks

The Differentiated Services architecture allows for the provision of scalable Quality of Service by means of aggregating flows to a small number of traffic classes. Among these classes a Premium Service is defined, for which end-to-end delay guarantees are of particular interest. However, in aggregate scheduling networks the derivation of such worst case delays is significantly complicated and the derived bounds are weakened by the multiplexing of flows to aggregates. A means to minimize the impacts of interfering flows is to shape incoming traffic, so that bursts are smoothed. Doing so reduces the queuing delay within the core of the domain, whereas an additional shaping delay at the edge is introduced. In this paper we address the issue of traffic shaping analytically. We derive a form that allows to quantify the impacts of shaping and we show simulation results on the derivation of end-to-end delay bounds under different shaping options.