A STUDY OF LATENCY AWARE CONTROLLER PLACEMENT PROBLEM IN SDN

Mili Dhar, Saikat Majumder

Abstract

In fast and rapidly growing technology where data handling is more important, a new promising paradigm
has come into the picture called Software-Defined Network (SDN). A SDN is a software-based
programmable network that detaches the control and data plane to overcome the shortcomings of
traditional networks. This separation provides many advantages like network virtualization, flexibility,
management, and so on. Apart from the advantages given by the SDN, it also brings some issues. The
controller placement problem (CPP) is one of them. Depending on the controller location network
performances can vary. Putting a controller in any of the accessible locations is also not a good idea, as it
only increases the overhead delay. Hence, selecting an appropriate location to shorten the latency is a
challenging task. Thus, in this article, we talk about the importance of latency in SDN and study some of
the latency-aware techniques developed by other researchers to solve the CPP. These solutions have been
divided into two categories according to the application scenarios which are data-center networks and
Wide Area Networks (WANs). We've categorized latencies in the control plane and presented their
mathematical formulation. We have also presented a comprehensive study in this review. Lastly, we
outlined potential areas for future research that researchers can delve into further.