SDN is an interesting concept adapted to give more control to network administrators to play around with how data traverses in a network. From access control lists to routing information, this empowers engineers to configure what they need minus the blackboxed codes made by vendors like Cisco and Juniper.
Sounds good? Yes its awesome, but how do you put this idea to a bunch of guys who only understand risks, accountability and standards of practice. I believe SDN is a dated technology which needs more focus on a common standards of practice. Lets leave that for another day.
What is SDN;
http://searchsdn.techtarget.com/definition/software-defined-networking-SDN
Want to learn for free?
https://www.coursera.org/course/sdn
First this is the link to the workshop;
http://ecs.victoria.ac.nz/Events/SDNWorkshop
Second; Mininet is an awesome emulator for SDN. Look for ryu-controller as well.
https://github.com/mininet
Third;
the big boys are in the game too, like VUW, Reanzz, Google and Catalyst. The government? Not sure.
leave me a note if you are keen to have a further discussion on this.