In this day and age of ever-expanding internet connectivity, human lives are completely reliant on the internet and the resources that it provides. Tasks that are performed on a daily basis are dependent, in some way or another, on the internet. Increasing the number of users leads to a growth in the amount of data, which in turn leads to an increase in the number of devices. Furthermore, according to human nature, the demand grows, which in turn leads to an increase in lust. It is necessary for humans to have the criteria of better and better being met. In this paper, a quick review of the network architectures is presented. These architectures are separated into two categories: the first is a legacy-based network architecture, and the second is an advanced and improved software-defined networking architecture. In order to answer the question of why legacy-based network architectures and infrastructures are still favored rather than SDN-based optimized network architectures, this paper is based on a survey that covers the demographic area of Pakistan as a majority. The survey was conducted in order to have an answer to the question. This study also discusses the literature that pertains to software-defined networks and the architecture of software-defined networks (SDN).

Index Terms- Legacy, Internet, SDN, Virtualization, AI-Router