Duplicated Switching Fabric And Its Scheduling Algorithms

The switching fabric is the central part of switches or routers, which determines the performance of switches or routers. Output-Queueing and Input-Queueing are two typical switching fabrics which are widely used in switches or routers. However, the scalability of Output-Queueing is poor for its buffers must work at the rate N times than the line rate. As saclable is Input-Queueing, there is a complex scheduler needed for resolving the switching contention of Input-Queueing. As a result, neither Output-Queueing nor Input-Queueing is fit for high-performance switching. So, how to make a trade-off among the scalability, performance and complexity of scheduler is a challenging problem in the design of high-performance switches.In this paper, an novel switching fabric, named duplicated ports switching fabric(DPS), is proposed. It uitilizes the space multiplexing technique to lower down the buffers working rate. Its validility and rationality is verified by the proof of the stable results and identical behavior between DPS and OQ. The applied algorithms for DPS scheduler are also investigated in the paper. Firstly, a queueing model for packet delay analysis is presented. Two delay-guaranteed scheduling algorithms are proposed and their delay boundedness is given using the queueing model. Then, iSLOT algorithm is designed which combines the Round-Robin and differentiate techniques. At last, exhaustive simulations are made for the performance comparison of kinds of maximal matching algorithms and iSLOT as scheduler of DPS.The theoretical and simulation results in this paper show that DPS is competent for high-performance switching in terms of scalability, performance and complexity of scheduling algorithms.