C.3 Untrusted Non-3GPP IP Access with PMIPv6 to Trusted Non-3GPP IP Access with PMIPv6 Handover in the Non-Roaming Scenario

23.4023GPPArchitecture enhancements for non-3GPP accessesRelease 18TS

This clause shows a call flow for a handover when UE moves from an untrusted non-3GPP IP access network to the trusted non-3GPP access network. PMIPv6 is assumed to be used on S2a and S2b interfaces.

NOTE: The procedure is also applicable to the handover within PMIP-based S2a interfaces or PMIP-based S2b interfaces.

Figure C.3-1: S2b to S2a (PMIPv6) Handover

This procedure supports the non-roaming (Figure 4.2.2.1), home-routed roaming (Figure 4.2.3-1) and roaming with Local breakout (Figure 4.2.3-4) case. The PCRF in the HPLMN is informed of the change of access and any change in the policy that results is signalled to the Trusted non-3GPP IP Access. The signalling takes place through the vPCRF in the VPLMN. In the case of roaming with Local Breakout, the PDN GW in the VPLMN exchanges messages with the vPCRF.

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

1) The UE is connected to the untrusted Non-3GPP IP Access. There is an IPsec tunnel between the UE and the ePDG and a PMIPv6 tunnel between the ePDG and the PDN GW.

2) The UE moves to a Trusted Non-3GPP IP Access network.

3) The access specific procedures of the Trusted Non-3GPP IP Access are performed. These procedures are outside of the scope of 3GPP.

4) The EAP authentication procedure is initiated and performed involving the UE, Trusted Non-3GPP IP Access and the 3GPP AAA Server. In the roaming case, there may be several AAA proxies involved. As part of the authentication procedure, the information of the selected PDN GW, e.g. PDN GW’s address, is conveyed to the MAG in the Trusted Non-3GPP IP Accesses.

5) After successful authentication and authorization, the L3 attach procedure is triggered.

6) The Trusted non-3GPP IP access initiates a Gateway Control Session Establishment Procedure with the PCRF as specified in TS 23.203 [19] to obtain the rules required for the Trusted non-3GPP IP access to perform the bearer binding.

7) The MAG function in the Trusted Non-3GPP IP Access sends Proxy Binding Update message to the PDN GW.

8) The PDN GW executes a PCEF-Initiated IP CAN Session Modification Procedure with the PCRF as specified in TS 23.203 [19] to inform the PCRF of the new IP-CAN type and obtain the updates to the PCC rules.

9) The PDN GW processes the proxy binding update and creates a binding cache entry for the UE. The PDN GW allocates IP address for the UE. The PDN GW then sends a Proxy Binding Acknowledgement to the MAG function in the Trusted Non-3GPP IP Access, including the IP address(s) allocated for the UE. The IP address allocated is same as that was assigned to UE before over the Untrusted Non-3GPP Accesses.

10) The PMIPv6 tunnel is set up between the Trusted Non-3GPP IP Access and the PDN GW.

11) L3 attach procedure is completed. IP connectivity between the UE and the PDN GW is set up for uplink and downlink direction over the trusted non-3GPP IP access.

12) The PDN GW initiates resource allocation deactivation procedure in the untrusted non-3GPP IP access as defined in clause 6.12 or clause 7.9.