Software-Defined Networks (SDN) and Network Function Virtualization (NFV) are two technologies that have already had a deep impact on computer and telecommunication networks. Software Defined Networks (SDN) decouple network control from forwarding functions, enabling network control to become directly programmable and the underlying infrastructure to be abstracted from applications and network services. Network Functions Virtualization (NFV) is a network architecture concept where IT virtualization techniques are used to implement network node functions as building blocks that may be combined, or chained, together to create communication services. SDN and NFV make it simpler and faster to deploy and manage new services, avoiding the cost and the long time frame required to design and implement hardware-based network services. Furthermore, these technologies allow the existing hardware infrastructure to be effectively used, as services can be (re-)allocated according to requirements, resources and load.

SDN and NVF introduce numerous dependability challenges. In terms of reliability, the challenges range from the design of reliable new SDN and NFV technologies to the adaptation of classical network functions to these technologies. The effective, dependable deployment of the virtual network on the physical substrate is particularly important. In terms of security, the challenges are enormous, as SDN and NFV are meant to be the very fabric of both the Internet and private networks. Threats, privacy concerns, authentication issues, and isolation - defining a truly secure virtualized network requires work on multiple fronts.