Networks have been protected and partitioned by physical or software-based firewalls for many years now. These devices are deployed in an attempt to protect resources and direct traffic in a safe and productive manner. In the past, a virtualization environment of any sort was totally reliant on physical firewalls for defense and advanced features, including Network Address Translation (NAT) and Virtual Private Network (VPN) services.

As the industry moves toward the era of Software Defined Networking (SDN) with protocols such as OpenFlow, the virtualization of traditional physical networking components becomes more prevalent. SDN enables the abstraction of network devices through a controller layer, which, in turn, communicates with the virtual services at the SDN layer. While still in its infancy at the time of writing this book, SDN promises to become the next evolution of networking and to offer further integration of virtual and physical network components. OpenFlow is...