So it is not related to DNS at all as we are talking about download acceleration in iTunes. That makes a lot more sense, thankfully.
It is normal to accelerate downloads by using multiple sources - download managers and torrent clients do this all the time. I just haven’t observed more than one stream from the same IP address.
If I have time I might see if I can force the same behavior in a generic download manager.
Download manager definition
A download manager is a computer program dedicated to the task of downloading possibly unrelated stand-alone files from the Internet for storage. Some download managers can also be used to accelerate download speeds by downloading from multiple sources at once. Although web browsers may have download managers incorporated as a feature, they are differentiated by the fact that they do not prioritize accurate, complete and unbroken downloads of information. While some download managers are independent programs that can download any data over one or more protocols, many are integrated into installers or update managers and used to download parts of a specific program; examples of the latter include Google's and Adobe's update managers.
