Implementing HLS/DASH Content Steering at Scale

Abstract

Content Steering is a recent addition to both HLS and MPEG DASH standards, enabling dynamic routing of streaming content between different CDNs and delivery pathways. Already supported by DASH.js, HLS.js, and several other players, it dramatically simplifies the design of multi-CDN systems. No custom client plugins, DNS redirects, or CMS integrations are needed. However, for HLS/DASH Content Steering method to operate, it requires new elements: content steering servers. This paper discusses how to design and deploy them at scale. The proposed solution effectively reduces the logic on the content steering servers to stateless operations, in which all state variables become parameters of the client-server exchange. Such design enables servers to be deployed very inexpensively at the edge (by utilizing edge functions offered by many CDNs or edge platforms). Ourproposed method is highly scalable, allows short response time, and enables a full spectrum of multi-CDN traffic optimizations: load balancing, failover protection, COGS- and QOE/QOS-based optimizations.