PC6/PC7 (application id: 16777340)

The PC6/PC7 interfaces enable communication between ProSe Functions located in different PLMNs (Public Land Mobile Networks), specifically between the Home PLMN (HPLMN) and local or visited PLMNs. The primary purpose of these interfaces is to support service authorization and management for ProSe services, such as ProSe Direct Discovery and communication.

PC6/PC7 workflow:

1. Service Authorization:
   • When a UE in a local or visited PLMN attempts to use a ProSe service, the request is first processed by the local ProSe Function.
   • The local ProSe Function uses the PC6 or PC7 interface to send a service authorization request to the ProSe Function in the HPLMN.
   • The HPLMN ProSe Function processes this request and determines whether the UE is authorized to use the requested service.
   • If authorized, the HPLMN ProSe Function sends a positive response back to the local ProSe Function, allowing the service to proceed. If not, the request is denied.
2. Direct Discovery Authorization:
   • A UE initiates a ProSe Direct Discovery request through the local ProSe Function.
   • The local ProSe Function forwards this request via the PC6/PC7 interface to the HPLMN for authorization.
   • The HPLMN ProSe Function evaluates the request and returns the authorization status to the local ProSe Function.
   • Based on the response, the local ProSe Function either allows the discovery process to continue or terminates it.
3. Discovery Filters and Application Code Translation:
   • When a ProSe service requires the application of specific discovery filters, the local ProSe Function retrieves these filters from the HPLMN ProSe Function via the PC6/PC7 interface.
   • The interface also facilitates the translation of ProSe Application Codes to their corresponding Application Names, ensuring that services are accurately identified and managed.

For complete technical specification of PC6/PC7 interface in Diameter protocol please refer to: [3GPP TS 29.345].