virtualized network function (NFV) (VNF)
Virtual network functions (VNF) are virtualized network functions. Unlike classic network functions, which run on existing hardware, virtual network functions are implemented in software.
In general, all network functions can be virtualized and implemented on virtual machines. Corresponding services are available for fixed and mobile networks. For example, the security functions of firewalls, the Domain NameSystem( DNS), the translation of network addresses or Network Address Translation( NAT). In mobile networks, it could be the Evolved Packet Core( EPC), the Mobility Management Entity ( MME), the Home Subscriber Service( HSS), various gateway functions, network nodes and other network functions that are virtualized. Corresponding services can be implemented by service providers or in enterprises.
As for the architecture of the virtual network functions, they are built on the Network Functions Virtualization( NFV) layer, which supports virtual network computing, virtual networking and virtual storage. NFV functions run on top of the NFV infrastructure (NFVI), with the various protocols and processes harmonized by a VNF manager.
Virtual Network Functions can be linked together in a service chain, which simplifies the provisioning and handling of the functions.