C.6 Handovers between APs of a Non-3GPP Trusted WLAN Access on S2a

23.4023GPPArchitecture enhancements for non-3GPP accessesRelease 18TS

No specific mechanisms are defined to support AP-to-AP handover with and without TWAG relocation. However, this does not preclude the support of IP address preservation in handovers without TWAG relocation when supported by procedures out of 3GPP scope.

Annex D (informative):
Void

Annex E (informative):
Gateway Relocation in the Trusted Non-3GPP IP Access

Gateway relocation within the Trusted Non-3GPP IP Access is possible using the procedures defined in this clause. The trigger for gateway relocation and any mechanisms for preserving or transferring context between gateways within the Trusted Non-3GPP IP Access is considered out of scope of this specification and should be handled within standards external to 3GPP.

In both the case of PMIPv6 and MIP v4 FACoA on S2a, the Gateway Control Session for the target gateway of the relocation is established before the intra-non-3GPP handover occurs. After the handover, the Gateway Control Session in the source gateway of the handover is terminated.

The mobility management and policy control signalling are both shown as optional messages. This is to allow flexibility depending on the requirements of the trusted non-3GPP IP access system. This allows a policy control signalling relocation (on Gxa) or a relocation of the local mobility anchor (S2a) or both (Gxa and S2a).