Glad to see mininet mentioned here. I used mininet academically for a graduate level course in computer networks, in combination with Pyretic (http://frenetic-lang.org/pyretic/), and it was a pleasure.

Spinning up a network topology simulation using mininet was effortless, and it proved to be an invaluable tool for network research. It's good to see other projects such as Shadow being developed in this space as well.