See also udptunnel, an older implementation of the same idea - http://www.cs.columbia.edu/~lennox/udptunnel/

The idea is pretty different. This one is implemented by a regular tcp socket, udp2raw is implemented by raw socket. Raw socket based implementation bypasses congestion control/retransmission/head-of-line-blocking, thus has much better theoretical performance.

Oh, really? Interesting, I had thought that udptunnel did as you suggest. Perhaps I was confusing it with something else.