Current traditional IP networks start to be complex as the demands of the users are ever-growing. Software Defined Network (SDN) is a new paradigm to ease the management of the network and make the network programmable by decoupling the control plane
and forwarding plane (such as switch and router). A centralized controller is used to manage the control plane, and it interacts with the forwarding plane using a standardized OpenFlow protocol. However, many controllers are used recently such as POX, Ryu, ONOS, and OpenDaylight. The important question is which is the best controller to use in our network and fits our network’s goals? To answer this question, a decision-making method is proposed in this paper. First, four SDN controllers are selected, and five criteria are analyzed to collect these controllers’ properties. Then a Multi-Criteria Decision Making method named TOPSIS is used to rank the controllers and choose the best one. By applying this method, a comparative study is done to evaluate the four controllers in an environment of LAN topology, and “Ryu” controller is selected as the best one based on our criteria.
Determining the best location is a complex process that faces decision makers. In the City of Tartous, Syria, this problem springs while selecting the best location for wastewater treatment plant (WWTP) because of the large number of criteria and co
nstrains and the uncertainty in expert's judgments. To solve this problem, we designed a frame work containing multi-criteria decision making (MCDM) technique that is fuzzy analytic hierarchy process (FAHP) to handle the uncertainty situations and geographical information system (GIS) to determine the best location.
In this paper, the FAHP idea was developed to calculate weights of the criterias, the GIS was used to overlay and generate criteria and suitability maps. The study ends with a map of the best sites for constructing wastewater treatment plants by extended aeration method in Tartous region in Syria.
