SCZ9.x-10.0 versions are non-compliant with TS29.214 (S8HR does not work)

Hello,

We have found out a bug on versions SCZ9.1, 9.2 and 10.0: S8HR mechanism does not work, because SBC does not receive a notification about PLMN-ID change from PCRF via Rx interface. According to section 16 of 5.3.13 of TS29.214, in case of PLMN_CHANGE a PCRF must report new PLMN-ID in response AAA during initial registration and RAR requests when PLMN change occurs. PLMN-ID shall be provided in attribute called 3GPP-SGSN-MNC-MCC. PCRF does not provide this data, because of missed AVP Supported-Features=PLMNInfo in AAR request that SBC generates during the initial registration of VoLTE subscriber.

In result SBC cannot recognize whether VoLTE terminal registers from home network or from visited network (roaming) and incorrectly handles IMS-AKA encryption. According to LI requirements IMS-AKA encryption must be disabled in case if subscriber is registered from visited networks (ealg parameter in 401 response to initial REGISTER must be set to 'null'). On every registration SBC gets the PLMN-ID info from PCRF, compares it to list of home/visited PLMNs in its S8HR profile and applies encryption based on match/mismatch.