# A Comprehensive Survey on Knowledge-Defined Networking
## 4 Management Plane
### Architecture of the Management Plane
Note that, as evident from Figure 5, the network monitoring module can use data contained in the management information base for network monitoring or can directly collect data such as flow statistics, topology information, etc., using protocols such as SNMP. Network monitoring can be basically used for fault management, mobility management, and energy management tasks in KDN [248]. The functioning of these tasks is discussed in detail in the application plane in Section 7.3.2. Note that applications can convey network monitoring policies through the network service abstraction layer to the network monitoring module of the management plane, which defines procedures and guidelines by which the particular monitoring task should be carried out. Furthermore, the knowledge plane can have an effect on network monitoring by providing knowledge or rules to aid in network monitoring. Note that, in KDN, both information- and data-driven network monitoring and knowledge-driven network monitoring can occur. In data- and information-driven network monitoring, which is the conventional network monitoring approach in SDN, the network is monitored based on information and data collected from the network. In knowledge-driven network monitoring, raw data collected about the network parameters are provided to the knowledge plane to generate knowledge regarding the network status, which will use the generated knowledge for network monitoring to decide on actions to undertake considering network policies. The configuration rules generated by the network monitoring module are provided to the network configuration module, which can be used to make decisions on network configuration considering rules or knowledge received from the knowledge plane and configuration policies received from the application plane. Note that the application plane can collect network configuration details, while the network configuration module can directly configure the network using a configuration protocol such as SNMP/OF-CONFIG, as shown in Figure 5. For instance, consider the previous example, where a configuration rule of \"Reduce energy consumption of each node by 20%\" is received from the network monitoring module to the network configuration module. Assume that there is a configuration policy specifying that \"the minimum energy consumption of a node should be 5% if the average network throughput is greater than 5 Mbps; otherwise, the minimum energy consumption of a node should be 10%\". Furthermore, assume that there is knowledge generated from the knowledge plane that specifies that the average throughput is 9.5 Mbps. Thus, by considering the available knowledge, the input configuration rule, and the configuration policy, the network configuration module can update the input configuration rules to output a new configuration rule to effectively reduce the energy consumption of each node. The updated rule for the given example should be \"Reduce energy consumption of the node by a maximum of 20% subjected to the constraint that energy consumption of the node is not lesser than 5%\". Note that the device configuration can occur iteratively for a few cycles until the network monitoring policy violation is lifted. More details on configuration rule generation and configuration policy enforcement are described in Section 5.4.3.