A Novel and High-Quality Measurement Study of Commercial CDN-P2P Live Streaming Content delivery network (CDN) and peer-to-peer (P2P) are two well-known techniques for the efficient distribution of video streams. We have designed and implemented a large-scale live streaming system by integrating the advantages of CDN and P2P technologies to overcome their own limitations. The system was commercially deployed by ChinaCache, one of the largest CDN companies in China. To the best of our knowledge, it is the first commercial CDN-P2P hybrid live streaming system that primarily adopts UDP transmissions among the end users. By leveraging a large set of log traces collected from the real system, we present important measurement results on various performance metrics, defined as resource allocation, dynamics, and user experience. The performance results demonstrate that the system holds the charming characters of scaling, fairness, and stability. The study of such a real system provides valuable insights into the future development and improvement of videostream technologies.