Software-defined networking (SDN) emerged in 2013 to be one of the hottest trends in networking. SDN wasn’t invented in 2013, it’s a concept that has its roots in a Stanford University thesis co-authored by Martin Casado in 2005, “The Virtual Network System.” The term SDN emerged in 2009. Ironically, Casado, the man who helped to create the SDN revolution, said in a video interview earlier this year that he no longer knew what the term SDN meant, because the definition has blurred as networking vendors big and small adopt the term to fit their own definition.