Large-file CDN caching

Design CDN caching for very large files (game/OS updates and 4K video segments, files of 5–50GB) where most clients only fetch ranges and the working set vastly exceeds any single PoP's cache capacity. You can't cache whole files at every edge node. Design the segmentation and tiered-caching strategy, how range requests map to cacheable chunks, how you handle a launch-day spike where everyone pulls the same new 40GB game, and how the mid-tier protects the origin.