IRIS-HiSA: Highly Scalable and Available Carrier-Grade SDN Controller Cluster

As software defined networking (SDN) extends its applications to carrier-grade networks, the need for high scalability and availability of a SDN controller is becoming increasingly important. Although existing works have shown the feasibility of a distributed controller, the switches in the data plane are required to know some of the internal specifics such as the IP addresses of the individual controller instances. This constraint increases the operational complexity as the number of controller instances increases. In this paper, we propose a distributed controller cluster architecture called IRIS-HiSA. The main goal is to support seamless load balancing and failover with horizontal scalability, as is done in existing works, but one of the distinguishing features of IRIS-HiSA is to provide transparency to the switches in the data plane. Thus, the switches do not need to know the internal details of the controller cluster, and they simply access it in the same way a single controller is accessed. In addition to proving seamless load balancing and a failover, a performance evaluation is conducted to analyze the high scalability in which the throughput of the flow setup is proportionally increased with the number of controller instances.