The interesting aspect of SDN is that the network responds to not only application demands, but also to changes in network behaviors. Cisco's view of SDN has a control mechanism, but more importantly it includes a feedback mechanism so the network paths can be recomputed on the fly, avoiding congestion because of impending oversubscription.
Private clouds are more than a trendy buzzword--they represent Virtualization 2.0. For IT organizations willing to dispense with traditional application hosting models, a plethora of pure cloud software options beckons. Our Understanding Private Cloud Stacks report explains what's available. (Free registration required.)