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.
Step 1.
A gateway relocation is triggered, to be initiated by the Trusted Non-3GPP IP Access. These trigger is outside the scope of 3GPP standardization.
Step 2.
The target Gateway in the Trusted Non-3GPP IP Access sends a Gateway Control Session Establishment message to the hPCRF.
Step 3.
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.
Step 4.
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.
Step 5.
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.
Step 6.
The PMIP tunnel from the target gateway to the PDN-GW is established.
Step 7.
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.
Step 8.
The PCRF sends an Acknowledge Gateway Control Session Termination message to the Trusted Non-3GPP IP Access acknowledging the termination of the control session.
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.
Step 1.
A gateway relocation is triggered, to be initiated by the UE. This trigger is outside the scope of 3GPP standardization.
Step 2.
The UE sends a Registration Request (RRQ)
RFC 5944 message to the FA. Reverse Tunnelling shall be requested. This ensures that all traffic will go through the PDN-GW. The RRQ message shall include the NAI-Extension RFC 2794 [34] and the Home Agent Address.
Step 3.
The Trusted non-3GPP access initiates the Gateway Control Session Establishment Procedure with the PCRF, as specified in
TS 23.203. The Trusted non-3GPP access provides the information to the PCRF to correctly associate it with the IP-CAN session to be established in Step 9 and also to convey subscription related parameters to the PCRF.
Step 4.
The FA processes the message according to
RFC 5944 and forwards a corresponding RRQ message to the PDN-GW.
Step 5.
The PDN-GW allocates an IP address for the UE and sends a Registration Reply (RRP) RFC 5944 [12] to the FA, including the IP address allocated for the UE.
Step 6.
The Trusted Non-3GPP Access Network initiates the Gateway Control Session Termination Procedure with the PCRF as specified in
TS 23.203. The Trusted Non-3GPP Access Network no longer applies QoS policy to service data flows for this UE.
Step 7.
The FA processes the RRP according to
RFC 5944 and sends a corresponding RRP message to the UE.
Step 8.
IP connectivity from the UE to the PDN-GW is now setup. A MIP tunnel is established between the FA in the Trusted Non-3GPP IP Access and the PDN-GW.