Paraget implements getting a single file in parallel from different mirror
sites.

Given that there are mirror-sites for the file one is downloading, one can
in principle accomplish a much greater bandwidth by downloading from all
the sites in parallel . This is accomplished by dividing the file being
fetched into several pieces, and by getting each piece from a different
server, and then re-assembling them.
   
If there are enough mirror sites, this partitioning makes it so that the
bottleneck is now placed at the client end, maxing the client's connection.

Paraget is designed to not only do basic n -equal-piece partitioning of a
file and sending requests out to n servers for data, but to also be dynamic
during the downloading process. For example if one server is too slow, and
paraget was done with faster server downloading its piece

WWW: http://paraget.sourceforge.net/