g devices enables infrastructure abstraction. Due to the abstraction, the network can be considered as a logical or virtual entity. In this chapter, relation between network kfunction virtualization (NFV) and software-defined networking (SDN) has been outlined. This chapter focuses on describing the pros and cons of NFV technologies. network functions virtualization (NFV) was founded under the work of the European Telecommunications Standards Institute (ETSI). DOI: 10.4018/978-1-5225-3640-6.ch002 Copyright © 2018, IGI Global. Copying or distributing in print or electronic forms without written permission of IGI Global is prohibited. Downloaded 4/15/2022 9:44:49 AM Nova Southeastern University IP Address: 137.52.76.29 Virtualizing Network Functions in Software-Defined Networks INTRODUCTION CDN: Content Delivery Network The term Network Function Virtualization (NFV) was initially announced in October 2012. A consortium formed by some leading telecommunication companies such as AT&T, BT, China Mobile, and Deutsche Telekom introduced the NFV Call to the Active document (Chiosi et al., 2013). Another new committee established under the European Telecommunications Standards Institute (ETSI) focused on improving the speed and operating standards. They worked on constructing the NFV standards and their work results as a white paper on Software-defined Network (SDN) and is entitled as "Network Functions Virtualization (Simone et al., 2015). This had been published by a specification group in Darmstadt, Germany. NFV, being a part of that work e ETSI and comprised of representatives from European telecommunication industry from Europe. They produced a standard terminology definition & use guiding the vendors and operators to facilitate better management and implementation of NFV. Herewith, a traditional standard for stability, quality and protocol adherence came into existence in a more refined manner (Borcoci, 2015). Understanding Relationship Between NFV and SDN The construction of NVF revolves around the key features of 