High performance network users are frequently unable to achieve adequate throughput when transferring large files across wide-area networks. In general, such poor file transfer performance over long fat networks (LFN) is primarily caused by limitations in transport protocols and network stack configurations on end-system hosts. In addition, some traditional file transfer applications have inherent design limitations that preclude optimized throughput performance across LFN environments. Several file transfer applications have attempted to address these limitations by supporting performance tuning, utilizing parallel data streams, and even leveraging different transport protocols. However, currently, no available file transfer solution simultaneously delivers high performance; enables end-users to easily install, manage, and use the application; and directly integrates with network layer provisioning tools. This project will develop a simple-to-use, intuitive file transfer application that provides a composeable dynamically tunable network stack, support for parallel data streams, and direct integration with network provisioning/resource reservation. Additionally, this tool will support a variety of file transfer protocols in order to maintain compatibility with existing file servers. Commercial Applications and other Benefits as described by the awardee The file transfer application should greatly benefit DOE scientists and researchers. End-users would finally be able to exploit scalable core infrastructures to significantly improve the performance and reliability of terabyte/petabyte bulk transfers.