TTCP (Test TCP) was designed many years ago as a UNIX utility for testing the speed of TCP and UDP connections between two machines. It is supported by some CISCO® devices (Cisco IOS® Software Version 11.2 or higher -- it is a hidden unsupported privilege command -- see Cisco Document ID: 10340 on their website for further information) and other UNIX systems. You must have a transmitter (server) and a receiver (client) set up on each machine. Once activated, connections are made and data (configurable size) is sent. After the data has been transferred, the actual link speed is calculated and displayed. The image below shows a session as a receiver.