(17-Nov-2011) APIs and messaging protocols, including some that are standards, can let users build software-defined networks today. The key issue, though, is that not everyone implements the same ones or implements them the same way. Will OpenFlow get us all on the same path to SDN nirvana?
OpenFlow is an open source API defined to enable multivendor switches and routers to be programmable through software on a central control element -- hence, "software-defined networking." It's designed to manage and direct traffic among routers and switches from various vendors by separating the programming of routers and switches from underlying hardware in order to provide consistency in flow management and engineering.
OpenFlow proponents say the API and protocol, and SDNs in general, will open up networks to more innovation by providing a level of abstraction, or virtualization, between network control and the physical infrastructure.