Design And Implementation Of Switching Unit Scheduling Algorithm And Queue Management In Space Station

As the switching fabric has a significant impact on the performance of local area network in space station, it can not only ensure a system work in the right way, but also reduce hardware resources and power as well as increase system bandwidth and throughput effectively. So the switching fabirc of local area network in space station is a key technology in the system research and design process.For the ethernet maturity and flexibility in networking as well as QoS assurance and hard redundancy supported by AFDX, and based on the research project "Research and implementation of High Performance Switch in Space Station", we propose a feasible network switching fabric, that is24×24three-stage Clos (6,4,6) switching fabric in MSM mode, which can provide both ethernet and AFDX services.Firstly, the conceptions and characters of switching ethernet, and related knowledge and networking characters about AFDX are introduced in this thesis. Then the principles and steps of CRRD scheduling algorithm in three-stage Clos network is deeply analyzed. Secondly, the general design and data processing flows of switching fabric in space station are explained. Thirdly, the specific designs of scheduling algorithm and queue management in switching unit are described in the next, and the realization of CRRD scheduling algorithm in packet mode (CRRD-PM) based on time slot and sharing memory queue management with DPRAM are particular described. Several key modules in scheduling and queue management, such as Rx_Central_Scheduler, Input_Scheduler, Matching_Module, T×_Central_Scheduler, Output_Scheduler, In_Queue_Controller, Out_Queue_Controller are presented and implemented in the thesis. Finally, the realizations of scheduling algorithm and queue management are simulated by Modelsim. The analyzing results prove that the design is accurate, reasonable, feasible, and as a whole, the design achieves the desired goals.