Software Defined Networks (SDN): Next Generation Network Architecture

To explain Software Defined Networks (SDN) in a better way, let's consider an example: My function is to send data and to control this function through message types. There are devices at each layer that regulate these messages. There are devices inserted at various layers, and we purchase and utilize them on the basis of their function.

SDN Layered Architecture Structure

For instance, a laptop is just a machine that acts based on the programs loaded into it. I cannot use it as a base station. To get Netflix, all of them need to connect to a base station, which inevitably creates a bottleneck. Therefore, we propose devices are simplified ("dummy") and a Control Plane is overlaid on top of them.

How Software Defined Network Architecture Works

In this approach, I will provide commands to these devices, and they will act according to these commands. Controllers will communicate with the devices at fixed intervals, but then the devices will act on their own according to their own intelligence and predefined rules—without any constant communication with the controller. This approach is called software-based architecture.

Software Defined Networks - Overview Architecture

Software Defined Network Administration

SDN seeks to provide open, user-controlled management of the forwarding equipment of a network. SDN exploits the ability to separate the data plane from the control plane of routers and switches. "The control plane is able to send commands all the way down to the data planes of the hardware."

Such a paradigm provides a view of the entire network, and allows global changes without device-oriented configuration on each hardware unit.

Global Centralization

One of the key ideas here is global centralization. Previously, each device had its own "brain." With the new idea, we extracted the local intelligence from devices and centralized it into one "big brain" at the top. In this architecture, the operating systems and application software that were originally inside the devices have been moved to the top controller, now the central brain. The devices themselves are merely their essential components—essentially just their ports and forwarding equipment. As a result, these devices become "dummy" devices, making up what is now called the Data Plane.

SDN General Architecture and Layers

Key Components of SDN Architecture

Application to Daily Use

For example, when I am home, my phone will no longer have to create a direct Wi-Fi or 4.5G link. Instead, the controller will make the connection for me and give me uninterrupted internet connectivity at all times. I won't even have to know with whom or what I am linking—the controller will do that.

Advantages and Challenges of SDN

Software-Defined Networking (SDN) introduces a more centralized architecture with some significant advantages despite some loopholes. With the passage of time, as demands from various locations became more intense and higher in frequency (spatially and temporally), it was clear that the controller-based architecture is a better option.

Main Advantages of SDN:

SDN represents the future of networking, allowing organizations to respond more quickly to changing business requirements while reducing operational costs.