storage which gives a different perspective for this book. These all topics all together make this book a different approach towards the topic of software defined network and network function virtualization which make this book different and unique from other. Thus focusing from the beginner to the advanced topic has been discussed in this book. The first chapter defined about software defined network which is not a new technology- we have been using concept of programmable networks for decades, this chapter describe the motivation behind SDN movement, its principles and perfect use cases and numerous technology related with SDN. Software defined network (SDN) and Network function virtualization (NFV) are the two new networking paradigms which are changing the way the traditional networks works. The SDN is the technology that works on the concept of centralization SO that all the decision related to controlling the networks should be taken on centralized place in a centralized manner. To provide a centralized control the SDN decouples the control plane and data from the traditional routing devices to take it in the centralized position. The data plane still intact with the routing devices but they now become a mere forwarding devices and the decisions are taken at the centralized place called the controller. Controller is basically the x86 server that are connect to the forwarding devices and communicate with them for all control decisions such as routing. NFV is based on virtualization of network functions in the form of software running over high end server. This kind of virtualization helps in easy setup of networks as well as easy migration. Downloaded: 4/15/2022 9:44:49 AM Nova Southeastern University IP Address: 137.52.76.29 Preface The second chapter discusses about network function virtualization. This chapter outline the benefits, enablers and challenges for network function virtualization. This chapter emphasizes that how the NFV is highly complementary to SDN. This chapter describe how NFV improve the 