Research On Multicast And Energy Conservation Technology In Fat-Tree Network

With the rapid development of the network,especially the popularity of bandwidth-intensive services,e.g.IPTV,telepresence and video conferencing,it has placed a great demand on the multicast switching technology because multicast is able to deliver the traffic in a resource-efficient way.However,resource contentions are more likely to occur if the cells are bound for multiple destinations.With the increasing of network traffic,the study of multicast switching technology with high-speed,large-capacity and energy-saving is becoming more and more important.This thesis studies on the multicast scheduling algorithm for input-buffered Crossbar.And based on it,an energy conservation algorithm used for Fat-Tree network is proposed.1.A multicast scheduling with low fan-out(MSLF)algorithm has been proposed.MSLF is an iterative algorithm,it can achieve low fan-out by using the improved queue structure and the dynamic weight algorithm,because it can ensure the output port to choose the same cell.The algorithm consists of four stages,packets preprocessing,iterative matching,packets transmission and HOL updating,and the iterative matching is the core of MSLF.A queue structure has been improved.Based on the traditional virtual output queue(VOQ),multicast status-words queues,multicast temporary-storage VOQs and independent queues are added for reducing the head-of-line blocking problem further.A dynamic weight algorithm has been proposed.Different from the existing algorithms that the weight remain fixed during each iteration,the new algorithm can calculate the weight dynamically according to the fan-out splitting of a multicast cell to give more chance to the low fanout splitting cells to export.A bi-directional shift priority setting method has been proposed.It's used for the calculation of dynamic weight.The bi-directional shift priority setting method is proposed for achieving the fairness while the traditional way has certain unfairness.The proof is presented in this thesis.MSLF coordinates all the algorithm into a unified system,and to ensure there is no disorder between cells.Good test results have been obtained both in traditional random traffic model and fixed traffic model.2.An energy conservation algorithm based on Fat-Tree network topology has been proposed.A simple but effective routing algorithm is proposed for 64-node Fat-Tree topology,and MSLF is used as the scheduling algorithm.Under the Bernoulli and Bursty traffic which using various proportion of unicast and multicast,good performance of simulation results has been obtained.