theastern University IP Address: 137.52.76.29 Introduction to SDN and NFV the defined flows on the switch, SO that when the next data packet arrives at the switch, and the matching rules are fulfilled, the data is routed according to the corresponding rules for that match, instead of sending it again to the controller. Therefore, by removing the complexities on the switches and routers, and instead managed and controlled from a logical centralized controller, the performance and flexibility are increased on the networks. SDN Data Path: The SDN Datapath is basically logical network device. The Datapath or logical device may contain all or a subset of its physical counterpart. An SDN Datapath consists of data forwarding engine, zero or more data processing engine and a controller to Datapath interface. These engines and functions may include simple forwarding between the data path's external interfaces or internal traffic processing or termination functions. A single physical device may contain more than one SDN data path or a single SDN Datapath may span across multiple physical network elements. SDN Control to Data Plane Interface (CDPI): The SDN Control to data plane interface provides the communication between an SDN Controller and an SDN Datapath. This interface provides Programmatic control of all forwarding operations Capabilities advertisement Statistics reporting Event notification CDPI is implemented in an open, vendor-neutral and interoperable way. SDN Northbound API: SDN Northbound API are interfaces between SDN Applications and SDN Controllers. The Northbound API provides abstract network views and enables direct expression of network behaviour and requirements. This may occur at any level of abstraction (latitude) and across different sets of functionality (longitude). One value of SDN lies in the expectation that these interfaces are implemented in an open, vendor-neutral and interoperable way. Challenges in SDN Network: A lot of research has been successfully conducted for SDN network on test bed ne