Background

Each time a new PNF is connected to the network, or reseted to factory settings, a PNF registration process is expected to happen.
Within this process, a VES pnfRegistration event is sent from a PNF instance to the ONAP/DCAE/VES collector.
In order to support Nomadic PNF use-case of a broader BBS use-case, an initial registration of a PNF needs to be distinguished from a re-registration.

Initial registration happens, when a PNF instance registers with ONAP for the first time (it was not used as a resource in any active service instance before).
Generally re-registration happens, when a PNF, that has been used previously in an active service instance, to deliver a service is re-connected or reset, and attempts to register again with ONAP with a pnfRegistration VES event.

Goal

The goal of this page is to summarize and prioritize the criteria, when a registration attempt is considered an initial registration and when - a Re-Registration.
All registration cases, which do not match with re-registration criteria will be considered "initial registrations".

...

SO project defined the State Machines, related to the service and resource (PNF/VNF) instances life-cycle.
The state machines are defined here. For PNFs, the state machine (simplified is stated as follows):

...

1. If a registration attempt is executed for a PNF Instance, which has an existing entry in the ONAP/AAI, and when that PNF instance is associated with an active (orchestration-status==active) service instance
   → Re-Registration
2. If a registration attempt is executed for a PNF Instance, which has an existing entry in the ONAP/AAI, and when that PNF instance`s orchestration-status field is set to "Registered"
   → Re-Registration (possible starting from ONAP/El Alto release, when a PNF mgmt state machine is implemented)