in improving the overall concept and allow taking 1.1 Cloud-Enabled 5G: SDN and NFV the concept to further applications in networking. First trials are currently under way in selected US universities, which focus on the easy management and reconfiguration of research networks, for example, for applications in the field of Clean Slate research. While SDN brings innovative evolution to network routers and switches, the network comprises other types of devices besides routers and switches. Network operators enforce network policies using a combination of switches and network functions (NF). Policies may be complex, such as ensuring that unauthorized users are prevented from accessing sensitive servers or malicious traffic is eliminated from the network. To do this, an operator could use a stateful firewall to ensure that only traffic initiated from within the network is permitted and in doing SO protect users from malicious traffic. Indeed, today's networks heavily rely on a wide spectrum of NFs. The diversity and complexity of NFs have been further expanded as the proliferation of wireless devices and mobile applications. NFs offer a variety of valuable benefits, ranging from improving security (e.g., firewalls, intrusion detection systems, and deep packet inspection), improving perfor- mance (e.g., proxies, caches) and reducing bandwidth costs (e.g., WAN optimizers, video transcoder). However, despite their benefits, NFs come with high infrastructure and management costs. One important reason is their complex and specialized processing. As a direct result of this complexity, configuration errors are common - configuration errors comprise as much as 65% of the network outages [9]. Other reasons of their complexity come from the lack of standardized man- agement tools across different devices and vendors. Moreover, there is a need to consider policy interactions between these appliances and other network infrastructure, which cannot be easily troubleshot. To facilitate programmability and flexibility of NFs, in 2012