VNFD

VNFD stands for Virtual Network Function Descriptor. In the ETSI Network Functions Virtualization (NFV) framework, the VNFD is the descriptive artefact that defines a single virtual network function (VNF) and its deployment, configuration, and lifecycle requirements. It is typically packaged together with related artifacts in a VNF Package (VNFP).

The VNFD provides the information needed by MANO (management and orchestration) systems to instantiate, configure, scale, and terminate a VNF on the virtualized infrastructure (NFVI). It specifies what resources the VNF needs (compute, storage, and networking), how these resources are allocated, and how the VNF interfaces with other network elements, including management and data plane interfaces. It also describes lifecycle operations and events such as instantiate, scale, heal, and terminate.

A VNFD is organized into sections that may include metadata (name, version, vendor), deployment units called Virtual Deployment Units (VDUs), and the connection points and requirements for virtual links. Each VDU maps to concrete resources or templates in the NFVI, such as virtual machines or containers, and details performance constraints, monitoring parameters, and dependency relationships. The descriptor can express different deployment flavors and scalability rules.

In the NFV architecture, the VNFD complements the VNF Package with the VNF’s artifacts and the Network Service Descriptor (NSD), which defines how multiple VNFs are assembled into a network service. VNFDs are commonly expressed in standardized formats defined by ETSI, and may be used alongside other modeling approaches such as TOSCA in some implementations.