Fast scheduler solutions to the problem of priorities for polarized data traffic

Three fast scheduling algorithms are proposed to handle efficiently polarized traffic in an advanced architecture for multiple-server optical IP packet routers. These schedulers must be capable of transferring several fixed-sized packets per port per time slot rather than one cell per time slot. An optical burst packet (OBP) contains a number of cells, obtained either from a network protocol or from segmentation. To optimize the resource utilization, it is important to maximize the filling ratio of these OBPs, but also important to adjust the right time-out to trigger the transfer of non-full packets. Moreover, the hardware implementation must be feasible and cost-effective. The solutions presented in this paper are detailed and compared by means of simulations. The first of them, MultiSLIP, is a generalization of iSLIP to the multiple-server architecture. The second one, PDRR, is a generalization of DRR (Dual Round Robin) to multiple-server architecture with priorities. The third one, FR-DRR (Flexible Ring DRR), features a new arbitration scheme based on a circular list of pending requests.