When the BPCF knows that a 3GPP UE attached via a Fixed Broadband access network and learns the IMSI and the NSWO-APN, the BPCF initiates the IP-CAN session establishment for NSWO offloaded traffic, the BPCF finds the PCRF using the DRA as described in clause 7.6.1
When the BPCF is requested to establish a Gateway Control Session over S9a by PCRF, the BPCF uses the PCRF address provided in the request to establish the Gateway Control Session over S9a.
In roaming scenarios, the selected V-PCRF shall belong to the same V-PLMN selected during the 3GPP access authentication procedure. The BPCF uses the VPLMN id to find the V-DRA in the VPLMN. The V-PCRF finds the DRA in the HPLMN based on the IMSI and the APN if available as described in clause 7.6.1
For PCRF discovery and selection by AF/TDF unsolicited application reporting for NS-WLAN offloaded traffic the procedure described in clause 7.6.1
When the DRA receives a request for a certain S15 Session establishment from the HNB GW, the DRA selects a suitable PCRF for the S15 Session based on HNB local IP address. When the S15 Session terminates, the DRA shall remove the information about the S15 Session.