QoS-aware Traffic Engineering in Software Defined Networks

In this paper, we propose a QoS-aware traffic engineering method in software-defined networks. Traditional shortest path based routing cannot guarantee future traffic demands because the routing only uses the minimum hop counts. The QoS-aware routing is more efficient than the traditional shortest path based routing; however, QoS parameters like link utilization and link delay are needed to perform such kinds of routing. The estimation of the link utilization and link delay may increase the controller computational time and load. To reduce the controller's computational time and improve the network resource utilization, the proposed QoS-aware routing method combines mainly two parts: the initial path calculation phase and link utilization aware path calculation phase. When the network is initialized, the first phase collects all possible paths for each pair of source and destination together with the link capacities and link delays. When the network topology changes occur or the collected paths do not satisfy traffic demands, the second phase re-calculates paths based on the link utilization and reroutes the traffic through the optimal path. Experimental results of throughput and packet loss rate show that our proposed method outperforms the other two methods.