Virtual Network Function (VNF) run specific network functions on virtual machines (VMs) under the control of a hypervisor in a Network Function Virtualization (NFV) enviroment - virtualization of network functions of service providers' network. VNF moves network functions out of dedicated hardware devices and into a software layer that runs on standard commercial off-the-shelf servers (COTs), promising a huge cost reduction for Operators' on their network expenditure. Operators also benefit from increased agility and faster time-to-market with new new services.
Firewalls, routing, DNS and caching are some of the early VNFs that are available in the market.