August 2026 Summaries

The journey of CDN selection at Mux highlights the challenges and evolution in finding an efficient and reliable method to choose content delivery networks. Initial attempts relied on third-party real user metrics (RUM) services, which proved insufficient due to limited control and data scope, leading to the development of a Mux-owned CDN selection process. This process initially faced issues with data dependence and latency-focused decision-making, ultimately leading to a more nuanced approach that prioritizes ruling out underperforming CDNs rather than finding the singular best option. The current system incorporates independent data sources and pre-calculated availability scores to enhance speed and adaptability, achieving a p99 latency of 9.9ms. Mux continues to improve this system by considering additional data sources and exploring content steering to further enhance resilience and performance.