Multi-server scheduling for high speed optical switches

High performance switching systems of the future will employ optical switching matrices to provide the required speed and capacity at competitive costs. Optical WDM technologies coupled with the need to concentrate data flow capacity at the switch matrix interface introduce the requirement for multiple queue servers at each input and output port. Such a multiserver architecture necessitates the development of novel scheduling algorithms. We developed and tested four iterative scheduling algorithms to assess their performance with respect to existing schedulers for mono-server architectures. A problem that arises because of multiservers in iterative scheduling algorithms is the proper matching of servers and grants after each iteration. We show an effective method to solve this problem and show the feasibility of the multiserver schedulers. The performance of these algorithms is comparable to or better than existing implementations. Switch speedup factors of one and two in combination with configurations of one, two, four, eight, and sixteen servers per port are demonstrated.