The topology that was created on the MiniEdit canvas constitutes of two default OpenFlow controllers. Every controller that is placed on the canvas is created with the default settings that are shown in the following screenshot. To create a stable topology, it is required that each controller operate on a unique port. By default, the controllers port are created with the same port number 6633. You are required to change the port number of every other controller; in this setup, we have controller c0 take port 6633 and controller c1 take port 6634: