If you want good cache hit ratios, you probably want to use segments as files rather than segments as byte ranges. Off the shelf http caching software tends to have filesize limits and may not cache large files in ram or even on disk if they're large enough, and may do unexpected things with range requests like request the whole file, then serve the range to the client. CDNs may be running totally custom http stacks or off the shelf stacks with tuned configs or somewhere in between, but if you intend to use one, it makes sense to build your content so it'll be easily cached.