One question that springs to mind is why invest in embedded physical SDN vSwitches which sit in-line between each and every appliance and their corresponding access ports? Why not simply apply the appropriate SDN configuration to the access switch on a per-port basis (assuming the access switch is SDN capable – of which there are a growing number)? Given that SDN (if present) is much more likely to be found in the data-centres and core networks than out to the access layer and remote branch offices, ONA would allow SDN policies to be pushed out further than existing SDN deployment would allow.