perations to view data exposed on the run-time state, events, and performance; to business and OSS that interact with real-time events; and customers in using, higher level interfaces where they need to configure services and integrate with their private infrastructure. 2.5.5 NETWORK SECURITY Security for networks is a multidisciplinary problem-starting with the classic security problems such as confidentiality and integrity, coupled with the problem of availability, that is, ensuring the service and network work, and can withstand a hostile attempt to bring it down. With Network Cloud, there is the need to understand security through the combined lens of software and network, in an operating cloud environment. For example, using the security technique of "defense in depth" Building the Network of the Future and "separations of concerns," it is a pragmatic approach to categorize VNF keeping each category type from running on the same server simultaneously. For these and other reasons, security is a key architecture and design factor for the Network Cloud. Security manifests itself from two different perspectives-the protection of the infrastructure itself and the ability to deliver security functionality in a service. The basic structure for infrastruc- ture security is to ensure each component is individually assessed and designed with security in mind. For the Network Cloud, the fabric component contains functionality such as access control lists (ACLs) and virtual private networks to limit and separate traffic flows. The servers run operat- ing systems with hypervisors that provide separate execution environments with memory isolation. Around this, operational networks are used to provide access to managements ports and use fire- walls to provide a point of control and inspection. Other aspects of security architecture also come into play. While the desire is to prevent a secu- rity problem, a good security approach also provides mechanisms for mitigation, recovery, and forensics. Mitigation approaches for inf