The biggest paradox of the Internet is that, being the epitomeness of freedom and openness, its actual implementation is even more closed than the old mainframes. And despite the fact that the whole thing has always been properly documented in RFC memorandums, the oddness and peculiarities of the concrete implementations have always lied hidden within router images, even for the most important inter-domain routing protocols, the biggest concern during interoperability tests.

So it turns out that the real definition of openness is a very nuanced one: in the software world, licensing and governance are paramount, meanwhile standards and interoperability are crucial and strategic in the networking world.

Fortunately, OpenFlow is unlocking a new window of openness in this closed world:  its approach to Software-Defined Networking enables reprogrammable traffic management techniques in the Layer 2 much like MPLS does in Layer 3, but in much more heterogeneous environments. Its first version is very featureless, missing IPv6, QoS, traffic shaping and high-availability, and lacking a killer app, its general adoption will take time, if ever. Even so, its ability to complement recent virtualization technologies in the data center, and being the only practical way for researchers to try out new experimental protocols, makes it a key technology to watch for in the next years.