5.9 UE-triggered Service Request for PMIP-based S5/S8

23.4023GPPArchitecture enhancements for non-3GPP accessesRelease 18TS

This clause contains the procedure steps that vary between the GTP and PMIP variant of S5 and S8 for the UE-triggered Service Request procedure defined in TS 23.401 [4], clause 5.3.4.1, for the case where the RAT Type reported in the Service Request has changed compared to the last reported RAT Type.

Figure 5.9-1: UE-triggered Service Request for PMIP-based S5/S8

This procedure concerns both the non-roaming (S5) and roaming case (S8). In the roaming case, the vPCRF in the VPLMN forwards messages between the Serving GW and the hPCRF in the HPLMN. In the case of Local Breakout, the vPCRF forwards messages sent between the PDN GW and the hPCRF as well. In the non-roaming case, the vPCRF is not involved at all.

The optional interaction steps between the gateways and the PCRF in the procedures in Figure 5.9-1 only occur if dynamic policy provisioning is deployed. Otherwise policy may be statically configured with the gateway.

A.1) The Serving GW informs the PCRF about the change of RAT type, UE Location Information IE and user CSG information (if this has been received from the MME preceding step A) by initiating the Gateway Control and QoS Policy Rules Request Procedure as specified in TS 23.203 [19].

A.2) The PCRF updates the PCC rules at the PDN GW by initiating the PCC Rules Provision Procedure as specified in TS 23.203 [19] if the PCC rules have changed based on the RAT type reported by the Serving GW in step A.1. The UE Location Information IE and user CSG information are also sent to the PDN GW from the PCRF (if this has been received from the Serving GW preceding step A.1).

Further, the hPCRF notifies the PDN GW of the change in RAT.

Step A.2 may be initiated before step A.1 completes: Once the hPCRF receives the event report from the Serving GW as part of step A.1, the hPCRF may complete step A.1 and initiate step A.2 in any order.