Multi-CDN Configuration and Dynamic Switching in AWS MediaTailor SSAI Environments – Part 1

When operating OTT services, many adopt a multi-CDN strategy to optimize costs and address quality differences by ISP. In particular, when introducing AWS Elemental MediaTailor for SSAI (Server-Side Ad Insertion), the challenge arises of deciding which CDN to use for delivering content segments versus ad segments respectively.

By leveraging MediaTailor's CDN Prefix settings, the two types of segments can be controlled independently. ContentSegmentUrlPrefix is used to specify the CDN domain for original content, while AdSegmentUrlPrefix is used to specify the CDN domain for ad creatives.

Furthermore, by combining Configuration Aliases with the domain variables feature, CDNs can be dynamically switched at runtime. When a player passes a specific Alias Key during session initialization, MediaTailor substitutes it with the pre-registered actual CDN domain, routing segments through the optimal path.