SDN多控制器部署及流量均衡研究

随着网络的发展，单一的控制器已经无法满足大量交换机的控制需要，需要使用多个控制器。利用改进的k-means++算法对网络拓扑图进行划分，将网络拓扑抽象为无向图，将网络中多控制器部署问题抽象为无向图的最短路径问题。以边的权重来划分图，权重由链路带宽和传输时延加权得出，比较2种方式的负载均衡度和成本得出多控制器部署策略。随后通过对网络中的多条路径采取流量均衡策略，使数据合理地分布在不同的路径上，使网络流量分配更平均，网络性能更高。实验表明，数据包在有多条路径可选择的情况下，可以合理选择传送路径，使网络中各个路径的负载更均衡。

SDN multi-controller deployment and traffic load balancing

With the development of network, a single controller cannot meet the control needs of a large number of switches, which needs to be handled by multiple controllers. This paper uses the improved k-means++ algorithm to divide the topological graph into an undirected graph and the shortest path problem of the undirected graph. The graph is divided by the weight of the edge, and the weight is weighted by link bandwidth and transmission delay. The load balance and cost of the two methods are compared to obtain the multi-controller deployment strategy. Subsequently, by adopting a traffic balanc- ing strategy for multiple paths in the network, the data is reasonably distributed on different paths, so that the network traffic is distributed more evenly and the network performance is higher. Experimental verification shows that when multiple paths are available for data packets, the transmission path can be selected reasonably to balance the load of each path in the network.