6.14 Non-3GPP access initiated IPv4 address Delete Procedure

23.4023GPPArchitecture enhancements for non-3GPP accessesRelease 18TS

This procedure is initiated by the Trusted non-3GPP access when the UE releases the IPv4 address using DHCPv4 procedure or the lease for the IP address has expired. The procedure is used to delete the IPv4 address from the PDN connection and bearer context.

Figure 6.14-1: Non-3GPP access initiated IPv4 address Delete Procedure

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

The roaming (Figure 4.2.3-1), Local Breakout (Figure 4.2.3-4) and non-roaming (Figure 4.2.2-1) scenarios are depicted in the figure. In the roaming case, the vPCRF acts as an intermediary, relaying the PCC messages between the hPCRF in the HPLMN to the BBERF/PCEF in the VPLMN. In the non-roaming case, the vPCRF is not involved at all. In the Roaming and LBO cases, the 3GPP AAA Proxy serves as an intermediary between the Trusted Non-3GPP IP Access and the 3GPP AAA Server in the HPLMN.

1. The MAG in the Trusted Non-3GPP IP Access sends a Proxy Binding Update (MN NAI, APN, lifetime=0, IPv4 only indication) message to the PDN GW with lifetime value set to zero, indicating de-registration. The MN NAI identifies the UE to deregister from the PDN GW. The indication for IPv4 only informs the UE that only the IPv4 address from BCE is to be deleted. The APN is needed in order to determine which PDN GW to de-register the UE from, as some PDNs may support multiple PDNs.

2. The PDN GW modifies the existing entry to delete the IPv4 address implied in the Proxy Binding Update message from its Binding Cache and releases all associated resources, and then sends a Proxy Binding Ack (MN NAI, APN, lifetime=0, IPv4 only indicator) message to the MAG in trusted non-3GPP access.

3. The PDN-GW initiates the PCEF initiated IP-CAN session modification procedure as described in TS 23.203 [19] to inform the PCRF of the deleted IPv4 address. If PCC rules have changed the PCRF provides the updated PCC rules to the PDN-GW as part of this procedure.

4. In case QoS rules have to be modified, e.g. change of SDF filters, the PCRF initiates a GW Control and QoS rules provision procedure as described in TS 23.203 [19] to inform the S‑GW of the updated QoS rules.

5. An IP‑CAN specific or resource release procedure may be triggered by the enforcement of the received policy rules.

6. The Trusted non-3GPP access informs the PCRF of the success of the QoS rules enforcement, thus ending the GW Control and QoS rules provision procedure described in TS 23.203 [19].