Instruction: OpenFlow Software$-$Defined Networking & OpenFlow: Software$-$Defined Networking $($SDN$)$ is a recently proposed networking paradigm in which the data and the control planes are decoupled from one another. One can think of the control plane as being the network$$s $$brain$,$ i$.$e$.,$ it is responsible for making all decisions, for example, how to forward data, while the data plane is what actually moves the data. In traditional networks, both the control$-$ and data planes are tightly integrated and implemented in the forwarding devices that comprise a network. The SDN control plane is implemented by the $$controller$$ and the data plane by $$switches$.$ The controller acts as the $$brain$$ of the network, and sends commands $($a$.$k$.$a$.$rules$)$ to the switches on how to handle traffic. OpenFlow has emerged as the de facto SDN standard and specifies how the controller and the switches communicate as well as the rules controllers install on switches. Mininet and OpenFlow: In project $1,$ we experimented with Mininet using its internal controller. We can also use our own designed controller to send commands to the switches. We will be using the POX controller, which is written in Python. OpenFlow $1\mathrm{.}3$ Overview: OpenFlow $1\mathrm{.}3$ is the version of the OpenFlow protocol supported within the Mininet environment. The following diagram explains the operation of OpenFlow switches.