Simulation of Software Defined Networks in Mininet environment Management of modern computer networks rapidly becomes more demanding due to complex user needs. Typical user tends to access content from different devices at any time. Due to multimedia content and mobile access, network traffic becomes more intensive, and network management more complex. A new paradigm, Software Defined Networking (SDN) enables network administrators to decouple control plane from data plane, and logically centralize control functions in a software controller. This paper describes SDN architecture and Mininet simulation environment for rapid SDN prototyping. A simple example of a real network is used to demonstrate programming of SDN controllers.