This document discusses network function virtualization (NFV), including its use cases, architecture, and virtualization requirements. It describes NFV's benefits in reducing costs and increasing flexibility compared to proprietary hardware appliances. The NFV architecture framework separates network functions into software-based virtual network functions (VNFs) that run on a shared virtualized infrastructure. It also covers NFV specifications, use cases like NFV infrastructure as a service, and virtualization requirements around performance, security, and resilience.