Up to this point, we have covered the details of OpenFlow functionalities and the role of OpenFlow switches and OpenFlow controllers in the SDN ecosystem. In Chapter 5, Setting Up the Environment, we set up our development environment, and in this chapter, we go through some network applications (Net Apps) using the POX OpenFlow controller and also the OpenDaylight controller that we introduced and set up in the previous chapter. Note that the potential and capabilities of OpenFlow controllers are more than the sample Net Apps that we introduce in this chapter. However, the goal here is to give you an initial push toward the basic steps in developing Net Apps using the OpenFlow framework. In the first part of this chapter, we will start with our OpenFlow laboratory (based on Mininet) and will go through the operation of an Ethernet hub, an Ethernet learning switch, and a simple firewall. Then, we will go through the details of a learning switch over the OpenDaylight controller.