Fundamental trade-offs in aggregate packet scheduling

In this paper we investigate the fundamental trade-offs in aggregate packet scheduling for support of guaranteed delay service. In our study, besides the simple FIFO packet scheduling algorithm, we consider two new classes of aggregate packet scheduling algorithms: the static earliest time first (SETF) and dynamic earliest time first (DETF). Through these two classes of aggregate packet scheduling, we show that, with additional time stamp information encoded in the packet header for scheduling purpose, we can significantly increase the maximum allowable network utilization level, while at the same time reducing the worst-case edge-to-edge delay bound. Furthermore, we demonstrate how the number of the bits used to encode the time stamp information affects the trade-off between the maximum allowable network utilization level and the worst-case edge-to-edge delay bound. In addition, the more complex DETF algorithms have far better performance than the simpler SETF algorithms. These results illustrate the fundamental trade-offs in aggregate packet scheduling algorithms and shed light on their provisioning power in support of guaranteed delay service.