6.13 PDN GW initiated IPv4 address Delete Procedure

23.4023GPPArchitecture enhancements for non-3GPP accessesRelease 18TS

This procedure is initiated by the PDN GW 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 bearer context.

Figure 6.13-1: PDN GW 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 PCEF initiates the IP‑CAN Session Modification Procedure with the PCRF as specified in TS 23.203 [19]. The PDN GW provides the information to enable the PCRF to uniquely identify the IP‑CAN session.

2. 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 Trusted non-3GPP access of the updated QoS rules.

3. The Trusted non-3GPP Access initiates the "Network-initiated Dynamic PCC on S2a" procedure to release the bearers.

4. 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].

5. The PDN GW sends a Binding Revocation Indication (PDN address) message to the trusted non-3GPP access to revoke the IPv4 address.

6. The trusted non-3GPP access returns a Binding Revocation Acknowledgement message to the PDN GW.