While OpenFlow has a centralized controller, that doesn't mean that each new flow has to result in a controller lookup. If a new flow matches an existing rule, it will be processed according to that rule's actions. Rules can be pre-populated, reducing the number of lookups that occur. Intelligent policy development should mean a reduced number of controller lookups. In addition, rules have a time to live associated, so if the switch is disconnected from the controller for some reason, it can still process existing and new flows. Only those flows that result in a controller lookup would fail.
Controller technology is not new either. Enterprises have been using controller-based wireless and network access control for years successfully.
Mike Fratto is a principal analyst at Current Analysis, covering the Enterprise Networking and Data Center Technology markets. Prior to that, Mike was with UBM Tech for 15 years, and served as editor of Network Computing. He was also lead analyst for InformationWeek Analytics ... View Full Bio