Software Defined WAN

The software-defined wide-area network (SD-WAN or SDWAN) is a specific application of softwaredefined networking (SDN) technology applied to WAN connections, which are used to connect enterprise networks – including branch offices and data centers – over large geographic distances.

Software-Defined Networking (SDN) is an architecture approach that separates the control plane from the data plane within network devices, such as switches and routers. In traditional networking, these planes are tightly integrated, meaning that the device itself controls both the forwarding of traffic (data plane) and the decision-making processes (control plane) related to how traffic should be handled.

In contrast, SDN decouples these functions and centralizes control over the network, allowing administrators to manage network behavior through software-based controllers. Key components and concepts of SDN include:

• Controller: The SDN controller is the central component of the architecture. It provides a centralized point of control for the network and communicates with network devices using standardized protocols, such as OpenFlow. The controller receives network-wide information and policies from applications or administrators and translates them into specific instructions for individual network devices.
• Southbound Interface: This interface connects the SDN controller to network devices, allowing the controller to communicate with switches, routers, and other networking hardware. Protocols like OpenFlow are commonly used to facilitate communication between the controller and network devices.
• Northbound Interface: The northbound interface enables communication between the SDN controller and higher-level network management applications or orchestration systems. This interface allows administrators to define network policies, set configuration parameters, and monitor network performance using APIs or other interfaces exposed by the controller.
• Data Plane Devices: These are the network devices responsible for forwarding traffic within the network. In an SDN architecture, data plane devices (e.g., switches, routers) receive instructions from the SDN controller regarding how to handle incoming packets. The devices implement these instructions by forwarding traffic according to the defined policies and rules.
• Network Applications: SDN enables the development and deployment of network applications that leverage the centralized control provided by the controller. These applications can implement various network services, such as traffic engineering, load balancing, security, and quality of service (QoS), by programming the behavior of the network devices through the controller.

Benefits of SDN include:

• Centralized Management: SDN provides a centralized view and control of the network, simplifying network management tasks and enabling consistent policy enforcement across the entire infrastructure.
• Flexibility and Programmability: SDN allows administrators to dynamically adjust network behavior and policies through software-based controllers, making it easier to adapt to changing requirements and optimize network performance.
• Automation: SDN enables automation of network configuration, provisioning, and management tasks, reducing manual overhead and improving operational efficiency.
• Scalability: SDN architectures are inherently scalable, allowing organizations to scale their networks more easily and efficiently by adding or removing network devices as needed.

Overall, SDN represents a significant evolution in networking technology, offering greater flexibility, scalability, and control over network infrastructure through software-defined approaches to network management and operation.