Abstract:Measurement technology plays an important role in the field of network researching as it is the foundation of researching on network monitoring, network management, and network security. Compared with the legacy network, software-defined network brings new research opportunities due to its advantages of standardization, openness, and transparency. The separation of measurement data plane and measurement control plane motivates the design and realization of more general and flexible measurement frameworks. Standardized API enables quick development and deployment of measurement tasks. Logically centralized controller enables the network to optimize the hardware configuration and forwarding strategy in real time by analyzing the measurement results pulled from SDN switches. The forwarding mechanism based on flow table enables data plane to provide more fine-grained measurement data of network traffic. However, challenges are also brought due to the contradiction between extra network overhead and the limited computing, memory, bandwidth resources in network. The centralized control plane may also suffer from performance bottlenecks. This paper reviews current researches on measurement methods of software defined networking from two aspects:framework and object, and then concludes the main research tasks and challenges. In the end, the argument about future research trend is elaborated based on existing research experiences.