From Richard Stanway:
The UDPXfer application was designed to be a small utility that will help users transfer single files to another host over UDP, supporting both active and passive connections. For most file transfers, TCP usually provides the highest speed and reliability. However, on high packetloss lines (20%+), the lost TCP segments cause excessively high delays between retransmits, which only get progressively worse as more packets are dropped. This results in transfers stalling and timing out.
To overcome the problem of TCP and high packetloss, UDPXfer constantly transmits random segments of the file to the receiver. The receiver then sends acknowledgements of which segments it has received to the sender, which will in turn stop transmitting those segments. The process continues until all segments are acknowledged. There are no timeouts or other such errors - the process will continue indefinitely until the receiver acknowledges all segments or one side aborts the process. This provides a way to reliably transfer a file over a very poor line at reasonable speeds. An SHA-1 hash is also added to each segment to ensure error-free delivery. This version is the first release on CNET Download.com.
What's new in this version:
This version is the first release on CNET Download.com.