a broken link, which will cut off some hosts and reduce the number of new packets into the controller. This will cause a drop in the entropy and a false positive. Five windows can give the network admin enough time to act. Downloaded: 4/15/2022 9:44:49 AM Nova Southeastern University IP Address: 137.52.76.29 Analysis of Issues in SDN Security and Solutions SDN OPERATIONS The SDN devices provides forwarding functionality for deciding what to do with each incoming packet. The devices also contain the data that drives those forwarding decisions. The data itself is actually represented by the flows defined by the controller, as depicted in the upper-left portion of each device. A flow describes a set of packets transferred from one network endpoint (or set of endpoints) to another endpoint (or set of endpoints). The endpoints may be defined as IP address- -TCP/UDP port pairs, VLAN endpoints, layer three tunnel endpoints, and input ports, among other things. One set of rules describes the forwarding actions that the device should take for all packets belonging to that flow. A flow is unidirectional in that packets flowing between the same two endpoints in the opposite direction could each constitute a separate flow. Flows are represented on a device as a flow entry. A flow table resides on the network device and consists of a series of flow entries and the actions to perform when a packet matching that flow arrives at the device. When the SDN device receives a packet, it consults its flow tables in search of a match. These flow tables had been constructed previously when the controller downloaded appropriate flow rules to the device. If the SDN device finds a match, it takes the appropriate configured action, which usually entails forwarding the packet. If it does not find a match, the switch can either drop the packet or pass it to the controller, depending on the version of OpenFlow and the configuration of the switch. Southbound API The interaction between the controller and the deployed device is commonly referred