 the elasticity to flex compute and storage resources required by different VNFs depending on the traffic patterns and distributions. It provides a new way to design, deploy, and manage network services. It decouples the network functions from purpose-built hardware, SO they can run in software. Most of the current focus in this space has been on virtualizing more and more network functions and cloud-like orchestration systems for managing deployed VNFs. 1.2.4 Software-Defined Networking SDN is a new approach to designing, building, and managing net- works, which enables the separation of the network's control plane and data plane, which makes it easier to optimize each. SDN has the potential to make significant improvements to service request response times, security, and reliability. In SDN, the controllers collect information from switches, and com- pute and distribute the appropriate forwarding decisions to switches. Controllers and switches use a protocol to communicate and exchange information. An example of such protocol is OpenFlow [13], which provides an open and standard method for a switch to communicate with a controller, and has drawn significant interests from both aca- demic and industry. In summary, NV, NFV, and SDN each provide a software-based approach to networking, in order to make networks more scalable and innovative. Hence, some common beliefs guide the development of each. For example, they each aim to move functionality to software, use general-purpose hardware in lieu of purpose-built hardware, and support more efficient network services. Nevertheless, note that SDN, NV, and NFV are independent, though mutually beneficial. Outline of Chapters This book is divided into five chapters and provides information on the different technologies that have been examined in the design of 5G next-generation networks. In Chapter 1, we introduce the background of carrier networks, the challenges of cellular network operations, and the requirements 1.3 Outline of Chapters for future network moving into 