Exploring load balancing of a parallel switch with input queues

Parallel switch is an emerging switch technology by which we can build a high capacity switching system (such as a terabit or higher switch) from many small switch fabrics. This paper refers to the parallel switch with input queues as the Buffered Parallel Switch (BPS) and address the open issue of load-balancing for switch fabrics working parallelly and independently. Two classes of definition which depict the load balancing in different ways are proposed. Then conditions for BPS load balancing are analyzed and a family of distributed scheduling algorithms is presented. At last, a simple and efficient scheduling algorithm which can satisfy both classes of definition in a BPS without speedup is developed. Simulation results show the validity and performance of the load-balancing algorithm. Practical implementation of the distributed scheduling algorithms is also discussed.