This technical report describes key issues and solutions for optimized offloading of traffic to WLAN access when PS mobility between 3GPP RAT takes place. The technical report analyzes the user and service impact due to mobility between 3GPP RATs. The technical report analyzes the key issues and solutions in order to identify whether current mechanisms documented in SA2 specifications are sufficient, identify potential inefficiencies, and identify whether additional solutions are needed to address the key issues. The technical report also describes proposed extensions to ANDSF in order to enable policy differentiation for 3GPP RATs (e.g. E-UTRAN versus UTRAN, GERAN versus UTRAN) with respect to WLAN, in order to enable a UE to distinguish preferences of WLAN with respect to specific 3GPP RATs upon acquiring connectivity (e.g. PDN creation in a 3GPP RAT or WLAN, or establishing NSWO connectivity) or upon mobility.

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