Software-defined load balancer in cloud data centers

Today's Data Centers deploy load balancers to balance the traffic load across multiple servers. Commercial load balancers are highly specialized machines that are located at the front end of a Data Center. When a client request arrives at the Data Center, the load balancer would determine the server to service this client's request. It routes the request to an appropriate server based on the native policies such as round-robin, random or others without considering the traffic state. It is not possible to implement arbitrary polices as load balancers as they are vendor specific. Apart from that, the piece of hardware is expensive and becomes single point of failure. In this paper, we develop a software defined network (SDN) based load balancing architecture with a load-aware policy using OpenFlow switch connected to SDN controller and commodity servers. It is less expensive when compared to the commercial load balancer and has programming flexibility in terms of applying arbitrary polices by writing modules in the SDN controller. With the facility of supporting multiple controller connections in commercially-available OpenFlow switches, the system is robust to single point of controller failures. We develop a prototype implementation of the proposed SDN based load balancer and carry out performance study to demonstrate its effectiveness.