Читать книгу The Smart Cyber Ecosystem for Sustainable Development - Группа авторов - Страница 49

The architecture of SDN is comprised of three planes:

 Data Plane: comprised of the forwarding devices, i.e., switches and virtual switches. Unlike distributed network architectures, in which switching and routing devices listen to events from neighboring network elements and make decisions based on a local view, switches and routers are responsible for forwarding, dropping and modifying packets based on policies received from the CP.

 Control Plane: The CP is considered to be the brain of SDN. It can program network resources and dynamically update the rules of forwarding, in addition to making the management of the network flexible through the centralized controller. The centralized controller controls communication between switches and applications. On the other hand, the controller exposes the network status and summarizes the information to the application plane. Also, the CP translates the requirements from applications to specific policies and distributes them to devices. Further, it provides the basic functions needed by most network applications such as routing algorithms, network topology, device configuration, and state information notifications.

 Application Plane: composed of network applications that define management and optimization policies to be applied on the network. Applications can get network state information from the controller and implement the needed control to change network behavior.

The inclusion of ML in SDN may require a new architectural structure that differs from the traditional of SDN. In [10], a new plane is proposed called the knowledge plane KP as shown in Figure 2.6. The KP hosts ML algorithms that use statistical learning to learn the network behavior. These algorithms contribute to decision-making. Hence, the KP in SDN communicates directly with the controller, which, in turn, asks the network elements to implement decisions.

The controller gets information from network devices through the OpenFlow protocol. A server is used to process information and run ML algorithms. The execution of recommended commands is the responsibility of the controller which is connected to the KP. On the top, the application plane is running to manage the network.

Figure 2.6 The SDN architecture with knowledge plane.