nuttcp is a network performance measurement tool intended for use by network and system managers. Its most basic usage is to determine the raw TCP (or UDP) network layer throughput by transferring memory buffers from a source system across an interconnecting network to a destination system, either transferring data for a specified time interval, or alternatively transferring a specified number of bytes. nuttcp is based on nttcp, but have several useful features such as a server mode, rate limiting, multiple parallel streams, and timer based usage. WWW: http://www.lcp.nrl.navy.mil/nuttcp/