Evaluating the Control and Management Traffic in OpenStack Cloud with SDN

The performance of cloud computing depends heavily on the networking infrastructure, which carries the data traffic between the VMs, as well as the essential control and management traffic. Meanwhile, networks in data centers are becoming softwarized with the Software Defined Networking (SDN) paradigm to fuel their programmability and flexibility. However, since SDN switches need to contact the controller frequently for their configuration and flow rules setup, the overall data traffic forwarding performance can suffer, if the control and management plane gets congested. In order to proactively avoid such congestion, we need to study the involved traffic in detail. In this work, we perform an elaborate traffic evaluation on a real OpenStack cloud deployment and evaluate the types of exchanged messages in the control and management plane and their respective traffic volume. The evaluation reveals that the control and management traffic scales with the number of VMs and the VM-related events, and therefore provides guidelines for planning and operating the cloud networking infrastructure.