Performance evaluation mechanisms for FlowMod message processing in OpenFlow switches

Network operators can benefit in terms of flexibility, cost, and vendor-independence when adopting the Software Defined Networking (SDN) paradigm. In many scenarios, the SDN controller orders the installation of new flow table entries in the switches it manages. Since such operations are handled in the slow path of the switches, the corresponding processing times constitute an important performance indicator for switches. This work focuses on a comparison of two mechanisms for evaluating the performance of OpenFlow switches with respect to the processing time of FlowMod messages. These mechanisms are characterized by different degrees of accuracy, cost, complexity, and the capability of performing measurements at run time. The first mechanism is based on the Spirent C1 dedicated testing platform, while the other uses a software module for the OpenDaylight controller. We assess their capabilities with respect to the abovementioned characteristics and quantify their accuracy by means of wiretaps that provide a ground truth regarding the measured processing times. By using three different switches in the experiments, it is possible to distinguish between hardware specific side-effects and general phenomena.