SL), for example, VDSL or FTTdp. These technologies require a dedicated electric system to be deployed on the street close to home. These devices are usually expensive as they need to tolerate all sorts of extreme environmental conditions. Access network functions virtualization can greatly simplify these remote devices. Among all these use cases, 1-4 are in the cloud computing area, 5 and 6 are in the area of mobile computing, 7 is for data center, and the last two are in the area of residential and access networks. Together they demonstrate the wide usage of NFV in today's network. Virtualizing NFs could potentially offer many benefits including, but not limited to, the following: Reduced equipment costs and reduced power consumption through consolidating equipment and exploiting the economies of scale of the IT industry. Increased speed of time to market by minimizing the typical network operator cycle of innovation. Economies of scale required covering investments in hardware-based functionality are no longer applicable for software-based development, making feasible other modes of feature evolution. NFV should enable network operators to significantly reduce the maturation cycle. 3.3 NFV Challenges Availability of network appliance multiversion and multitenancy, which allows the use of a single platform for different applications, users, and tenants. This allows network operators to share resources across services and across different customer bases. Targeted service introduction based on geography or customer sets is possible. Services can be rapidly scaled up/down as required. Enables a wide variety of ecosystems and encourages openness. It opens the virtual appliance market to pure software entrants, small players, and academia, encouraging more innovation to bring new services and new revenue streams quickly at much lower risk. 3.3 NFV Challenges Carrier-grade properties: The telecom service providers have high requirement on the performance, scalability, fault tolerance, and secu- rity on the solutions.