Re:The concept is great, but... (Score 5, Informative)

Hello. I'm the designer of PDTP.

...mirrors would need to be in sync at all times for this to work. Otherwise your PDTP client is only able to download from the mirrors that are in sync, or worse, will get some chunks from files that aren't up-to-date, causing problems. Unfortunately, it's (almost) impossible to mirror new files instantaneously, so mirrors are never all in sync, all the time.

I suggest you look at this page with graphic illustrations of PDTP networks for a better idea of how PDTP works. There is no concept of a "mirror" in a PDTP network. The Source Server is the central authority on all files being distributed over the network, and notifies all servers/piece proxies on the network whenever files become available or unavailable. Like BitTorrent, the network is largely self-sustaining, with clients uploading pieces to each other and verifying their integrity with MD5 or SHA1 checksums. Files are tracked on the network with integer keys, so if a file were altered its name would simply be mapped to a new key, and the entire network would be notified that the previous version is no longer available.