hroughput, one solution is to manage the bandwidth usage of each network flow. On an Open Flow switch device, Downloaded: 4/15/2022 9:44:49 AM Nova Southeastern University IP Address: 137.52.76.29 Quality of Service in SDN Technology Figure 6. Simulation of service implementation Local Area Network Internet 10 Mbps 1000 Mops 1000 Mops 25 Mops Switch 10 Mops Leg Graph Color Option two ways can be used to control the bandwidth usage of each network flow. One is to use meter table and the other is to use the per-port output queues. Here in this chapter, in Figure 7 we display an example case that has almost the same network topology as the one mentioned above. The only difference is that we replace the legacy switch in the LAN by an Open Flow switch, to which an SDN controller is connected. To provide a QoS service to the traffic-destination nodes, we classify them into three groups: the guaranteed group, the fairly-shared group, and the contended group (Chui, Yang & Ding, 2004). The total quantum of bandwidth of the wireless link (i.e., 25 Mbps) is assigned to these three groups: 10 Mbps for the guaranteed group, 12 Mbps for the fairly-shared group, and 3 Mbps for the contended group. For those nodes belonging to the guaranteed group, we want to reserve fixed quantum of bandwidth to each one. In this example case, 6 Mbps is reserved for Node 1 and 4 Mbps is reserved for Node 2. For those nodes belonging to the fairly- shared group, we want them to fairly share the assigned quantum of bandwidth. In this case, Node 3, Node 4, Node 5, and Node 6 belong to this group and each of them Downloaded: 4/15/2022 9:44:49 AM Nova Southeastern University IP Address: 137.52.76.29 Quality of Service in SDN Technology Figure 7. Design of model for service implementation Data Center Controller Server Server Server Rack 1 Rack 2 Rack 3 Guaranteed Local Area Network Internet Quota 10 Meps SDN Controller Fairly- shared BOUTHAGULIN 1000 Mbps 1000 Mbps Quota: 12 Mbps SON Barrich 10 Mbps 1000 Mbps Contended Quota: 3 Mbps should obtain 3 M