VNF Descriptor (VNFD) based on ETSI NFV-SOL001

This document describes how to create your VNFD files based on ETSI NFV-SOL001 v2.6.1. The VNFD is modelled by using one or more TOSCA service template as defined in TOSCA-Simple-Profile-yaml-v1.2. The VNFD is a component of a VNF package and takes YAML format files.

The VNFD is composed of four different kinds of files:

Type definition files - define properties of each resource. Topology template files - describe the actual design of VNF.

ETSI NFV types definition file
User defined types definition file
top-level topology template file
topology template file with deployment flavour

Example:

Definitions/
      !---- etsi_nfv_sol001_common_types.yaml
      !---- etsi_nfv_sol001_vnfd_types.yaml
      !---- vnfd_top.yaml
      !---- vnfd_df_1.yaml
      !---- ..
      !---- vnfd_df_x.yaml
      !---- vnfd_types.yaml

Deployment Flavour Model

To design VNF with a VNFD, "deployment flavour model" is helpful. An example of the model is shown below:

The top-level topology template file describes the abstract design of VNF. In the example, the VNF has a Connection Point (CP) to an External Virtual Link (ExtVL). The CP and Virtual Link (VL) are mapped to a Port and a Virtual network, respectively.

The actual design of VNF is described in topology template files with deployment flavour. In the example, two different deployment flavours, "simple" and "complex" are provided. The "simple" has only a Virtualised Deployment Unit (VDU), which represents a VM while the "complex" has two VDUs. It is possible to design plural topologies for a VNF with deployment flavour. The deployed topology is specified with a deployment flavour ID in the Instantiation request parameter.

Type Definition Files

Type definition files contain all required "Types" appeared in service template files. The resources described in topology template files are defined as "Types" in type definition files.

There are nine groups of type definition in NFV-SOL001 v2.6.1.

Data Types: data_types
Artifact Types: artifact_types
Capability Types: capability_types
Requirements Types: requirements_types
Relationship Types: relationship_types
Interface Types: interface_types
Node Types: node_types
Group Types: group_types
Policy Types: policy_types

1. ETSI NFV Types Definition File

ETSI NFV provides two types definition files¹ which contain all defined type definitions in NFV-SOL001 v2.6.1. These files are generally imported from top-level service template file.

2. User Defined Types Definition File

Users can extend their own types definition from NFV-SOL001 v2.6.1. In most cases, Users need to extend tosca.nodes.nfv.VNF to define your VNF node types. The contents in the file are:

tosca_definitions_version - is always "tosca_simple_yaml_1_2".
description - is the description of the file.
imports - are the types definition files from ETSI NFV.
node_types - is the key to describe the extension of tosca.nodes.nfv.VNF to define your VNF.
(optional) data_types - is the key to define your own data types.

The tosca.nodes.nfv.VNF type described in node_types field is defined in section 6.8.1 in NFV-SOL001 v2.6.1. Its required properties are:

descriptor_id - is "VNFD ID" and required when creating VNF instance.
descriptor_version - is version of the VNFD.
provider - is name of provider who provide the VNFD.
product_name - is name of the VNF.
software_version* - is version of the software for the VNF.
vnfm_info - is identifies VNFM(s) compatible with the VNF described in this version of the VNFD. The default can be "Tacker".
flavour_id - is ID of deployment flavour to be used in Instantiation.
flavour_description - is description of the deployment flavour. The default can be "" (empty string).

Topology Template Files

The topology template files describe the topology of VNF. The topology is defined with the following contents:

tosca_definitions_version - is always "tosca_simple_yaml_1_2".
description - is the description of the file.
imports - are the types definition files from ETSI NFV and the user defined types definition file.
topology_template - describe the topology of VNF with node templates.

The topology_template field is defined in section 3.9 in TOSCA-Simple-Profile-yaml-v1.2. All keys are optional, but some keys are important to describe the topology:

(optional) description - is the description of file.
inputs - is a list of input parameters.
node_templates - is a list of node template definitions.
(optional) relationship_templates - a list of relationship templates.
groups - is a list of group definitions whose members are node templates defined within the same topology template.
policies - is a list of policy definitions.
outputs - is a list of output parameters.
substitution_mappings - is a declaration that exports the topology template as an implementation of a node type.
(optional) workflows - is a map of imperative workflow definition for the topology template.

3. Top-level Topology Template File

The top-level topology template file describes the abstract design of VNF. In this file, the node_template is provided with user defined VNF type derived from tosca.nodes.nfv.VNF. The file includes:

tosca_definitions_version: tosca_simple_yaml_1_2
description: A description of this file.
imports
- etsi_nfv_sol001_common_types.yaml
- etsi_nfv_sol001_vnfd_types.yaml
- <user defined types definition files>
topology_template
- inputs:
  - selected_flavour: The deployment flavour selected in Instantiation
- node_templates:
  - <name of VNF>:
    - type: The user defined VNF Type derived from tosca.nodes.nfv.VNF
    - properties:
      - descriptor_id: The VNFD ID created by User
      - descriptor_version: The version of VNFD
      - provider: The name of provider
      - product_name: The name of product
      - software_version: The version of VNf software
      - vnfm_info: ["Tacker"]
      - flavour_id: { get_input: selected_flavour }
    - requirements: The properties provided in lower-level topology template with a deployment flavour

Note

The required properties are defined in section 6.8.1 in NFV-SOL001 v2.6.1. The flavour_description is provided in the lower-level topology template and not included here.

4. Topology Template File with Deployment Flavour

The lower-level topology template provides a deployment flavour ID and its detailed design of VNF. The abstract design of VNF with user defined VNF Type is referred from substitution_mappings key and also added some properties in node_templates. The node_templates field contains the detailed resources such as VDU and CP. The file includes:

tosca_definitions_version: tosca_simple_yaml_1_2
description: A description of this file.
imports
- etsi_nfv_sol001_common_types.yaml
- etsi_nfv_sol001_vnfd_types.yaml
- <user defined types definition files>
topology_template
- inputs:
  - descriptor_id: The VNFD ID created by User
  - provider: The name of provider
  - product_name: The name of product
  - software_version: The version of VNf software
  - descriptor_version: The version of VNFD
  - vnfm_info: The identifies VNFM(s) compatible
  - flavour_id: The deployment flavour ID
  - flavour_description: The description of deployment flavour.
- substitution_mappings:
  - node_type: The user defined VNf Type
  - properties:
    - flavour_id: The deployment flavour of this file
  - requirements:
    - virtual_link_external: A list of CP and VL for external network
- node_template:
  - VNF resource
  - VDU resources
  - CP resources
  - VL resources
  - Other resources
- policies:
  - Scaling resources
  - Affinity resources
  - Other resources