udp_copy2 consists of two executables, udp_send2 and udp_recv2, implementing plain text non-interactive data transfer over UDP/IPv4 with a preset transfer rate. On lossy links, it yields better throughput than TCP-based transfers. It may also be used for smooth user space throttling. It dedicates a mode to SNAT/MASQ so the receiver can initiate transfer from behind a firewall. It features a very precise user space packet scheduler. It handles SIGSTOP in a rational way. It only transfers in one direction for one invocation. It needs and uses no synchronous I/O multiplexing. Shell access is required on both ends. The package also contains the auxiliary multi-threaded tool "bigpipe", which can be used to reduce pipeline latency.
