1. DF design as a node type

2. Overview: multiple DFs with TOSCA_matching
Matching rules:
First, the node type of DF in the VNFD service template matchs the one defined in substitution mapping of lower level DF service template.
Second, the matching is based on the flavour_ID property
DF_1 service template
VDU_1
VDU_2
Substitution mapping
node_type: tosca.nodes.nfv.df.DF_example
properties:
flavour_id: flavour1
VNFD service template
TOSCA_matching
DF node template
DF:
type:tosca.nodes.nfv.df.DF_example
properties:
flavour_ID: get_input: flavour_ID
VL_1 or
DF_2 service template
VDU_1
VDU_2
VDU_3
TOSCA_matching
The first matching rule is the normal substitution mapping, since there are multiple DFs for a VNFD, the type of the DF node template in the VNFD service template will map to two DF service templates (DF_1 and DF_2).
The second matching rule is based on the node filters matching as defined in tosca-simple-profile-yaml-v1.2, which the value constraint of flavour_ID property of the DF node template in the VNFD service template shall match to the flavour_ID property of one of the DF service template defined in the substitution mapping part.
Substitution mapping
node_type: tosca.nodes.nfv.df.DF_example
properties:
flavour_id: flavour2
VL_1

3. Overview: single DF design
DF_1 service template
VDU_1
VDU_2
Substitution mapping
node_type: tosca.nodes.nfv.df.DF_example
#properties:
#flavour_id: flavour1
VNFD service template
mapping
DF node template
DF:
type:tosca.nodes.nfv.df.DF_example
#properties:
#flavour_ID: flavour_1
VL_1 or
If there is only one DF in a VNFD, only the substitution_mapping mechanism to map the DF service template and the VNFD service template is applied.
The type of the DF node template in VNFD service template will only map to one DF service template.
In this case, tosca-simple-profile-yaml v1.0 or v 1.1 is enough to be used for the VNFD design and parse.

4. Deployment flavour service template design
DF_1 service template
Policy?
VDU_1
VDU_2
workflow?
VL_1
Group
capability
Policy?