Understanding Operational CDN Live Streaming: A Measurement Study on Performance, Costs, and Enhancements

The escalating need for live video streaming has emerged as a significant catalyst for the business expansion of today’s content delivery networks (CDN). Selecting the right CDN live streaming architecture is fundamentally important in achieving the objective of enhancing users’ quality of experience (QoE) while reducing bandwidth costs. Regrettably, a limited number of studies have been conducted to systematically measure and compare the current typical solutions at production scale. Consequently, the performance and costs of different streaming architectures remain myths. This paper aims to address the existing research gap by undertaking a large-scale measurement study of three representative CDN live streaming architectures, defined by streaming protocol and overlay topology choices, currently running on Alibaba Cloud’s production video delivery network. By analyzing the results of over 500 million video plays over two months on a large live streaming platform hosted on Alibaba Cloud’s CDN, we reveal the impact of architectural compositions and operational factors on live streaming performance and bandwidth costs. In particular, our study reveals the trade-offs between QoE metrics and bandwidth costs for operational streaming architectures. Drawing upon the insights of this study, we further develop and deploy pragmatic strategies that yield remarkable real-world impact—our design saves over 17% bandwidth costs while maintaining the QoE.