dr_patel_an: Summarizing the discussion of this email thread to just make sure that we all are on the same page.
The HPA requirements of a VNF are extracted from a VNF descriptor and captured in a TOSCA model in a tuple format (for the sake of extensibility purpose). Some of these requirements cannot be change during the lifecycle of a service; while the other optional requirements can be overwritten by a service designer or operator (For example, the use of SR-IOV may be preferred by an operator if a VNF can support SR-IOV and a vendor does not have a preference). Once a service model is designed and uploaded into the SDC repository, the policy service is notified. The policy service then fetches the TOSCA model, extracts out the HPA requirements from TOSCA through decomposition, composes the HAP polices for the homing service (OOF-HAS), and stores in the policy repository. When the homing service receives a homing request from SO, the homing service asks for the associated HPA policies from the policy platform. Based on the received HPA policies, the homing solution finds and returns the placement solutions.