Load balancing for multicast traffic in SDN using real-time link cost modification

In this paper we propose an approach for applying traffic load balancing to multicast traffic through real-time link cost modification in a software defined network (SDN) controller. We present an SDN controller architecture supporting traffic monitoring, group management, and multicast traffic routing. An implemented prototype is described, and this prototype is used to implement shortest path multicast routing techniques which make use of the real-time state of traffic flows in the network. This prototype is evaluated through experimentation in Mininet emulated wide area networks. Evaluation is presented in terms of resulting network performance metrics focusing on the distribution of traffic flows. Our results demonstrate that real-time modification of links costs produces statistically significant improvements in traffic distribution metrics, with an average improvement of up to 52.8% in traffic concentration relative to shortest-path routing. This indicates that SDN enables the use of real-time modification of link cost functions as an effective technique for implementing traffic load balancing for multicast traffic.