Introduction
Supporting ASD deployment in NSD is required in cloud native service deployment. ETSI NFV SOL001 has NSD defined. THis NSD structure could contains one or more VNF node template.
The proposed solution is to use the NSD to support ASD without any NSD standardization impacts. It only requires a sub-set of the existing NSD functionality which is needed for ONAP to define. The ASD support would be provided by an ONAP tailored “NFVO-light” with a sub-set of the NFVO functionality and an integrated ASD application manager component. The ONAP NFVO-light could expose a subset of the ETSI NFV SOL005 as an internal SMO interface. This would be a natural consequence when using the ETSI NFV NSD, rather than inventing a new NBI. However, this “NFVO-light” shall be standardized in ONAP so that vendor provided ASDs + NSDs can be onboarded into ONAP.
NSD referring to ASD
In order to avoid any changes to the NSD standard, the way to refer to a VNF as a VNF node template in the NSD shall be kept the same. This means that the VNF node template shall have an ETSI compliant VNF node type definition, derived from the tosca.nodes.nfv.VNF node type and the NSD will use this node type to refer to the ASD package. Meaning a generic “ASD_in_NS” node type is defined derived from the ETSI VNF node type, with default/fixed values for any property not used by the ASD and a number of generic virtual link requirements. The vnf_profile property in the ETSI VNF node type shall be possible to used to define the VNF cardinality in the NSD
The “ASD_in_NS” node type definition for the ASD must be included in both the NSD CSAR and the ASD CSAR package as it is referred from both the NSD and ASD yaml.
In the NSD the ASD package will be referred using the VNF node type descriptor_id. An NFVO that supports onboarding of ASD packages would need to have logic to identify the ASD package based on this descriptor_id. It is supported by exposing an ASD-unique descriptor_id as a substitution filter in the ASD TOSCA yaml file.
The NSD shall also support a VNF package invariant id for the ASD package
NSD features that shall be supported for the ASD
- The NSD shall still support to define min/max number of instances within the vnf_profile
- This will be used in order to support flexible deployment of ASD instances
- The existing SOL005 support for Instantiate NS with zero occurrence of some VNF instances and Update NS in order to add VNF instances later can be used for this
- The external virtual link requirement mapping towards NS Virtual Links is required
–The simplification will be to define a fixed set of Virtual Link requirements in the ASD_in_NSD node type definition
–If a fixed set is not seen as sufficient it would also be possible in TOSCA to just define one Virtual Link requirement with occurrence [1, UNBOUNDED]
–Instead of references to cpdIds an implicit reference based on the cpdIds list order will be used, first cpdId using first Virtual Link etc.
- The NSD shall support NSD specific NS additional params
–It could be relevant to define a number of ORAN pre-defined NS additional params, e.g. for target cluster name/id