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 buffers. In addition
to reporting the achieved network throughput in Mbps, nuttcp also
provides additional useful information related to the data transfer
such as user, system, and wall-clock time, transmitter and receiver
CPU utilization, and loss percentage (for UDP transfers).