Implementation and Experimental Evaluation of the Rebalancing Algorithm for Folded Clos Networks

Folded Clos network (FCN) is an important topology as it plays a significant role in building high-performance data center networks. To exchange packets over an FCN, traffic load must be uniformly diffused to fully utilize its high bandwidth. As a method to do this, the rebalancing algorithm was proposed. Previous studies have demonstrated the effectiveness of the method through theoretical analysis and computer simulation. However, its practical feasibility has not been elucidated. Moreover, its performance has not been confirmed on a physical experimental environment. This paper reports how the rebalancing algorithm is implemented on switches built on PCs using software tools supported by the Linux OS. This confirms that it is relatively easy to practically implement the algorithm. In addition, the performance of the implemented algorithm was assessed and compared with that of a conventional method through an experiment. As a result, the rebalancing algorithm was found to be more advantageous in avoiding traffic congestion for heavy traffic and flows with different sizes.