Clearly, there is an urgent need to maximize the resourceutilization of those existing pre-installed devices/boxes, as well as abstract these security resources to provide a simple interface for network tenants to use (who may not be aware of the exact security device information such as location). Motivated by this problem, we propose a new concept of Network Security Virtualization (NSV) that leverages preinstalled,
static security devices and provide dynamic, flexible, and on-demand security services to the users. Therefore, users do not need to know the concrete location/number of each kind of security devices/boxes. To realize NSV, we propose two new techniques: (i) transparently controlling flows to desirable network security services, and (ii) enabling network security response functions on a network device.