rce and true benefits of virtualization technologies to end customer (Figure 10.2). It is clear that once this new model is developed, it would provide significant cost savings to customers. It not only eliminates the middle-box problem discussed in the previous section, but also provides a software-centric approach to solving networking problems in a premise environ- ment. Customers will only be required to deploy limited hardware resources at the customer premise at the beginning. Subsequently, all the network use-cases can be implemented by instan- tiating and inserting the appropriate network function software as traffic passes through the CPE. In addition, the concept can be expanded further to evaluate another model whereby service chains are extended between network functions, across the WAN network. In this model, one can instantiate multiple network functions on the CPE platform and/or a cloud platform. Irrespective of where the functions are instantiated, it could be deployed and managed with the same set of tools. Enterprise Networks Physical VNF SW Physical Appliance X.86 Server Appliance X.86 Server Single network Function on Multiple network Function service- one x86 platform chained together on one x86 platform FIGURE 10.2 Shift to multiple VNFs. The customer would choose where best to deploy a function, either locally on premise or in cloud for multiple branch locations (Figure 10.3). With this vision, we embarked on this evaluation by putting together a proof of concept of a very simple topology, a single network function (virtual router) running on a x86 server platform. The very first question one had to answer was which virtualization environment to use for the project, that is, which hypervisor. The hypervisor is a program that enables hosting of several different virtual machines on a single physical server (see Chapter 3). In this form of virtualization, the underlying physical hardware is still working as an independent appliance while the hypervisor is providing the role of hardware virtu