A Systematic Review of Quality of Services (QoS) in Software Defined Networking (SDN)

In modern life the internet has become backbone of digital society which is the packet switched distributed network and connected with almost every digital devices, available everywhere in the world. The traditional network carries few challenges like, dependency on vendors, difficulty to manage large network, dynamically changing of forwarding policies and more. To overcome such challenges, today the idea of Software Defined Networking (SDN) came into existence. The basic idea behind SDN is to implement programmable network by separately managing the control plane and data plane to improve the efficiency of network performance. The main problem with SDN is the Controller Placement Problem (CPP), which gives the overview of whole network. Today the main focus of the researchers is to solve the CPP. CPP is a NP-hard problem because the network should consist of minimum controllers and controllers should be placed on appropriate locations. For the large size network, controller deployment is difficult to manage. But the challenge in this area is Quality of Services (QoS) in respect of controller management. This paper investigates the systematic review of QoS based on controller's problems, analyzed the current research and summarized the findings of the different controller's performance based on QoS parameters e.g. reliability, scalability, consistency and load balancing. Finally, this paper also highlights the research challenges to improve the QoS in SDN.