From the website: The FLExible Network Tester
Flent is a Python wrapper to run multiple simultaneous network benchmarking tool instances (e.g. netperf/iperf/ping) and aggregate the results.
Quote from an email back on 2016/07/22:
It uses "netperf" transfers to load the link (by default with 4 simultaneous TCP connections in both directions, IIRC), and then runs another test (by default "ping") at the same time to test the connection under load. Turning on a netperf server is just as easy as turning on an iperf server (and the results are better, and netperf's maintainer responsive).
Quote from email this morning:
I really encourage you to use flent with the rrul test suite when doing testing. Iperf is too simplistic and suffers from burstiness.