etwork cloud shared infrastructure components are protected and continually monitored for security events. 3. The network cloud elastic infrastructure will enable dynamic security control for VNFs and network services: All the features of a network cloud on-demand elastic cloud-like platform that protect against a failure also protect VNFs and network services against a potential security breach or attack. A compromised VNF VM can be quickly iso- lated, shutdown, quarantined, and replaced by another instance of a secured VNF VM. If an entire site is compromised then all the VNFs at that site can be replicated to other sites (although, due to redundant distributed design this may not be necessary except in extreme cases). 4. Hypervisor technology will provide another layer of security: VNFs can run as soft- ware modules and processes under any modern multiprocess operating system (i.e., any version of Linux). Although using the same physical hardware, virtualization tech- nology (via hypervisor) implements a strong partitioning of resources and isolation between VMs. It further implements strong VM quarantine or isolation capability for each software element on the network cloud shared infrastructure. Therefore, should a VM be compromised, the corrupted VM can be terminated and the VNF can be instantiated somewhere else. 9.4.4 HYPERVISOR AND OPERATING SYSTEM SECURITY NFV moves operations such as routing and FWs onto the hypervisor. Figure 9.11 depicts how infra- structure components and network traffic flows are expected to change with the introduction of NFV. The previous section highlights a traditional application stack where each component is on a physi- cally separate hardware. Therefore, all the network traffic traverses physical connections. In the future, when the operating system has been virtualized and now the traffic between some compo- nents at the top of the stack may only traverse the virtual connections established on the hypervisor. Building the Network of the Future OSI Model Present Future Layer