Research On Clos Network Multicast Switching Technology

With the explosive growth of information services and the rapid development of broadband optical transmission technologies, the network nodes have gradually become the bottleneck of broadband networks. Switches and routers are the main interconnected devices of the backbone transmission network, so the research on high-performance switches and routers has important theoretical and practical significance. Switch architecture and scheduling algorithm, as the key technologies of high performance switch and router, even determine the performance of the routing switching devices, so a comprehensive study of them is key to solving the problem. The three-stage Clos switching fabric is widely used in core routers and switches. The three-stage Clos network switch fabric, compared with the traditional switching architecture, can provide greater switch capacity, for its capability of connecting multi-small switch unit together. The design of scheduling algorithm is based on the specific switch architecture, while the performance of the switch architecture is largely dependent on the scheduling algorithm design, so in order to improve the performance of the switching system, we must consider the switching fabric and scheduling algorithm both.In this thesis, the multicast scheduling algorithms of high-capacity Clos switching fabric are studied. The architecture of the three-stage Clos switching fabric, non-blocking conditions, fan-out mechanism and a variety of the existing multicast scheduling algorithms are also studied. Strengths and weaknesses of the existing three-stage Clos fabric multicast scheduling algorithms are summarized, on the basis of which the architecture of the MSM is improved, and a Central Module First Fanout Multicast Algorithm based on Buffered Central Module (CMFFMAB) is proposed. Simulation results show that the algorithm in the general traffic models can achieve good performance.