In this paper, we show the effectiveness of software shaping through evaluation of our extensions to the internet transport protocols, TCP (Transmission Control Protocol) and UDP (User Datagram Protocol). These extensions are aimed at efficient realization of bulk data transfer and continuous media communication. The extensions are to be used with resource reservation, a possible and promising approach to resolve transport issues that the current TCP/IP networks cannot support. Although it seems straightforward to utilize dedicated bandwidth set up via resource reservation, filling up the reserved pipe is not so trivial. Performance analysis shows that, by applying the traffic shaping extensions, not only is the reserved pipe easily filled up, but the timely data delivery required by continuous media communication is also provided. Our experiments with a real system also show that overheads introduced by the new extensions are small enough to permit their practical use. The extensions are implemented in the UNIX system kernel.