This paper proposes a framework on controller and switches to reduce overhead of controller-switch communication for SDN-based Data Center Networks (DCN). The proposal focuses on OpenFlow (OF), a well-known, sophisticated protocol for SDN, to reduce the number of control messages, consisting of both PACKET_IN and PACKET_OUT messages handled by the OF controller during rule installation on OF switches¡¯ flow tables. The controller receives the first packet of a flow for forwarding path determination and selectively chooses switches for rule installation. Moreover, to ensure lower loads for the controller to handle, the proposed framework adds an out-of-band controller and avoids a hybrid architecture. Extensive simulation shows significant results on reduced controller workload. The performance provides a mutual trade-off by considerably improving rule matching rate in the presence of slightly enhanced number of flow entries, conserving resources on both OF controller and OF switches for SDN-based DCN operation. As a consequence, network latency is reduced while throughput is enhanced, which offers a great promise in the future deployment of DCN.
Available online: https://www.sciencedirect.com/science/article/pii/S0920548917304427