n some cases, many flow entries for one user. This level of flow coarseness would merely not scale if it were applied nearer to the network core, wherever nice switches touch upon the traffic for tens of thousands of users at the same time. In those core devices, the flow definitions are going to be typically additional course, with one mass run entry matching the traffic from an oversized variety of users whose traffic is mass in how, like a tunnel, a VLAN, or a MPLS LSP. Policies applied deep into the system can doubtless not Downloaded: 4/15/2022 9:44:49 AM Nova Southeastern University IP Address: 137.52.76.29 SDN Controller be user-centric policies however rather policies that apply to those mass flows. One optimistic result's that there'll not be associate explosion within the variety of flow entries within the core switches because of managing the traffic emanating from thousands of flows in border switches. (How SDN Works, n.d.) THREAT VECTORS IN SDN Software-defined networks have two properties which can be seen as good-looking honey pots for malicious users and a basis of headaches for less ready network operators. First, the capacity to control the system by means of software (always subject to bugs and a score of other weakness). Second, the centralization of the network intelligence in the controller(s). Anyone with access to the servers can potentially control the entire network. Threat Vector 1 Forged or faked traffic flows, which can be used to assault switches and controllers. This risk can be triggered by defective (non-malicious) devices or by a malevolent user. An attacker can use system elements (e.g., switches, servers, or personal computers) to start on a DoS attack next to OpenFlow switches (e.g., targeting to exhaust TCAMs) and controller resources. A simple authentication machine could mitigate the difficulty, but if an attacker assumes the control of an application server that stores the particulars of numerous users, it can easily use the same authenticated ports and source MAC addresse