You might be wondering about the difference between OpenFlow 1.0 vs. 1.3, and what happened to OpenFlow 1.2. OpenFlow 1.0 represents the very first effort to introduce the concept of programmable flow in switches to the world. It includes a limited subset of switch-matching and action functions, but many in the industry do not consider OpenFlow 1.0 to include sufficient features for production networks. It is really about the introduction of the concept and showing the potential of the technology to the industry.

The concept was well received by the industry, and the standard makers were quick to start working on iterations of the specification, such as version 1.1 and 1.2. However, hardware implementation of a technology takes much longer than the speed at which the specifications are written. Many of the vendors cannot keep up with the speed of specification releases. It became obvious that the specification needs to slow down a bit and work with equipment makers so there can be actual hardware to run our networks when the specification comes out. OpenFlow 1.3 was written in conjunction with equipment makers' timing to have hardware switch support. It is the first version of OpenFlow considered by many to be production ready.

Now that we have learned about the basics of OpenFlow, we are ready to take a look at the protocol in action. But before we can do that, we will need a switch that understands OpenFlow as well as a few hosts connected to that switch. Luckily, Mininet provides both. In the next section, we will look at Mininet, a network emulation tool that we can use to experiment with OpenFlow.