Mininet
Mininet creates scalable (up to hundreds of nodes, depending on your configuration) Software-Defined (e.g. OpenFlow) Networks on a single PC by using Linux processes in network namespaces.
It allows you to quickly create, interact with, customize and share a software defined network prototype, and provides a smooth path to running on hardware.
To download Mininet and get started, go to the Download page.
Mininet's source code is hosted on GitHub at http://github.com/mininet/mininet.
Alternately, you may wish to learn more about Mininet or peruse the Mininet Documentation.
Please direct any Mininet-specific questions to our helpful mininet-discuss mailing list -- NOT to nox-dev, ovs-discuss, or openflow-discuss.
Have fun with Mininet!!