When the Gateway Relocation procedure occurs in the Non-Roaming case (Figure 4.2.2-1), the vPCRF is not involved.
In the case of Roaming (Figure 4.2.3-1) and Local Breakout (Figure 4.2.3-4), the vPCRF is employed to forward messages from the hPCRF in the home PLMN, by way of the vPCRF in the VPLMN to the non-3GPP access.
A gateway relocation is triggered, to be initiated by the Trusted Non-3GPP IP Access. These trigger is outside the scope of 3GPP standardization.
The target Gateway in the Trusted Non-3GPP IP Access sends a Gateway Control Session Establishment message to the hPCRF.
The PCRF responds to the target Gateway an Ack Gateway Control Session Establishment (QoS Rules, Event Triggers) message. The PCC rules provide the PDN GW with information required to enforce the dedicated bearer policy. The event triggers indicate to the PDN GW when to report an event back to the PCRF related to the dedicated bearer.
The target Gateway sends a Proxy Binding Update (MN NAI) message to the PDN GW to register the UE at the PDN-GW. The MN NAI identifies the UE.
After creating the binding cache entry for the UE, the PDN GW responds with a Proxy Binding Acknowledgement (MN NAI, Lifetime, UE Address Info) message to the MAG. The MN NAI repeats the UE identity sent previously. The Lifetime expresses the duration of validity of the binding. The UE Address info includes the allocated IP Address(es) corresponding to the IP CAN session.
The PMIP tunnel from the target gateway to the PDN GW is established.
The source Gateway in the Trusted Non-3GPP IP Access system sends a Gateway Control Session Termination to the PCRF. This gateway ceases to perform Bearer Binding and associated policy controlled functions.
The PCRF sends an Acknowledge Gateway Control Session Termination message to the Trusted Non-3GPP IP Access acknowledging the termination of the control session.