Anything the cache doesn’t have, causes a cache miss, which passes it through. So when you request the large file, the CDN (cache) doesn’t have it, so it immed

Anything the cache doesn’t have, causes a cache miss, which passes it through. So when you request the large file, the CDN (cache) doesn’t have it, so it immediately passes through to the original source. The details of how this is implemented don’t really matter in the sense that they are not going to host the large file(s) in the CDN, so they will always fall through.